Constructing a Rule Based Naming System for Thai Names Using the 
Concept of Ontologies 
Chakkrit Snae 
Department of Computer Science 
Naresuan University 
Phitsanulok, Thailand 
chakkrits@nu.ac.th
Abstract
Names are important in many societies, 
even in technologically oriented ones 
which use ID systems or other ways to 
identify individual people. Names such 
as personal surnames are the most im-
portant as they are used in many proc-
esses, such as identifying of people, re-
cord linkage and for genealogical re-
search as well. For Thai names this 
situation is a bit different in that in Thai 
the first names are most important. 
Even phone books and directories are 
sorted according to the first names. 
Here we present a system for construct-
ing Thai names from basic syllables. 
Typically Thai names convey a mean-
ing. For this we use an ontology of 
names to capture the meaning of the 
variants which are based on the Thai 
naming methodology and rules. 
1 Introduction 
Names are used for identifying persons, places, 
things and even ideas or concepts. Names serve 
for labelling of categories or classes and for indi-
vidual items. They are properties of individuals 
which are of greater importance in most commu-
nities. In technological oriented societies such as 
modern Western the reference between names as 
a label and the person is not as obvious as in 
small tribal societies. This is especially true 
where names are stored within large information 
systems. This includes government, medical, 
educational and even commercial records which 
are kept about individuals. Names are the most 
important referrer to a person even if there are 
numbering systems like ID numbers because 
such systems are not universal. Names are often 
queried in a different way than they were en-
tered. Names represent complex lexical struc-
tures which have to be handled systematically for 
data entry, storage and retrieval in order to get 
sufficient recall or precision the retrieval process 
in.
In this paper we present a first account of our 
findings on constructing Thai names with the 
help of an ontology of names as well as a work-
ing methodology for the naming process in Thai 
culture.
This paper is organized as follows: Section 2 
contains a description of names and their ele-
ments. In Section 3 we outline the concept of 
ontology of names. In Section 4 we present the 
construction process and system for Thai names. 
We apply this system together with an ontology 
to construct names with an appropriate meaning. 
Section 5 shows the conclusions of our study and 
further work which has to be performed. 
2 What is a Name? 
Names for individuals are often called proper 
names, for humans sometimes also an-
throponyms. Names for places are called 
toponyms, for bodies of water hydronyms, for 
ethnic groups ethnonyms, for metaphors meto-
nyms and so on. Names are more than just 
strings of characters. Names show important in-
formation such as titles, gender, marital status, 
and even birthplace. For this names provide dif-
ferent elements (Section 2.2), which may differ 
between cultures.
86
2.1 Naming for Identity and Security 
From the technical point of view we want to link 
and match as many names as possible with the 
correct individuals. If we deal with individuals of 
the same name, e.g. John Smith, we have to es-
tablish a second identifier at least. This can be – 
and is in many cases – a temporal element, like 
the date of birth, which is an individual and un-
changing property of the person. Another way to 
circumvent the problem is to establish numbering 
systems, like ID numbers. Systems of numbers 
or other ciphers can be generated within individ-
ual organisations. It is not likely that the result-
ing ID numbers will be the same in different or-
ganisations. The numbering may have limitations 
as well, e.g. the individual health care setting 
(e.g. within a hospital or district) or, in principle, 
more widely (e.g. the National Health Service 
number). In the past, the National Health Service 
number in England and Wales had serious limita-
tions as a matching variable, and it was not 
widely used on health-care records. With the al-
location of the new ten-digit number throughout 
the NHS all this has been changed (Gill, 1997).  
Although numbering systems are simple to 
implement they can lead to different errors in 
recording, transcripting, and keying. So we have 
to take into account methods which reduce these 
errors and facilitate good quality of data entry 
and retrieval. One such method uses a checking 
device such as check-digits (Wild, 1968, Ham-
ming, 1986). When we are not able to use unique 
numbers or ciphers, natural matching variables 
are the person's name, date of birth, sex and per-
haps other supplementary variables such as the 
address with postal code and place of birth, 
which are used in combination for matching. Re-
cently, it has been suggested that this simple 
code could be extended for security critical 
places (e.g. airports, checkpoints etc.) with bio-
metric marker information extracted from person 
identifier information e.g. finger-
prints/iridograms. 
2.2 Elements of Personal Names
The following table shows typical elements of 
personal names together with potential variations 
and sources of choices, e.g. dictionary of given 
names.  
Figure 1: The elements of names 
3 Ontology of Names? 
The term ontology has been widely used in re-
cent years in the field of Artificial Intelligence, 
computer and information science especially in 
domains such as, cooperative information sys-
tems, intelligent information integration, infor-
mation retrieval and extraction, knowledge rep-
resentation, and database management systems 
(Guarino, 1998, Andrade and Saltz, 1999, 2000). 
Many different definitions of the term are pro-
posed. One of the most widely quoted and well-
known definition of ontology is Gruber's (Gru-
ber, 1993): An ontology is an explicit specifica-
tion of a conceptualization.
The term is borrowed from philosophy, where 
an ontology is a systematic account of existence. 
Here in this paper we adopt the following defini-
tion: Ontology is the study or concern about what 
kinds of things exist - what entities or things are 
there in the universe (Blackburn, 1996). Our 
work on ontologies will comprise: a terminologi-
cal component where we lay down the concepts 
and an assertional component (or Knowledge 
Base) which contains the individual instances 
(entities). The level of description will be tax-
onomies with hierarchically related terms and 
controlled vocabularies (thesaurus) with the help 
of semantic networks. 
An ontology of names can be worked out in 
many different forms, but every ontology will 
include a dictionary, some definition of the terms 
87
(semantics), and indications how they depend on 
each other, e.g. in hierarchies and semantic net-
works. For example, an ontology of names can 
be defined as what kinds of names exist, e.g. first 
name, surname, nickname, etc (Section 2.2). This 
typically comprises definitions of different 
names, the elements of names and their struc-
tures. In this section we show how an ontology 
of names can be captured and defined. 
An ontology can also be used to establish the 
network of synonyms, e.g. using spelling norms 
to determine whether two names are the 
same/similar or not.  For example, two names: 
Totie and Totiey can be defined based on as-
sumption that they are the same as Totty. This 
attempts to tackle the seemingly irreducible con-
ventions of surname. In compositional semantics 
let us consider the name “Gutensohn”. This name 
will be used to illustrate the various semantic 
considerations in German naming. The name is a 
composition of the two strings Godith and Sohn, 
which have unambiguous, meaningful interpreta-
tions. The interpretation of Godith is god or good 
battle and Sohn is interpreted as a male child in 
relation to his parent.  The composition Gutsohn, 
Gudzon, or in other cultures: Guditson, Godye-
son and Godithson and Godison (Reaney and 
Wilson 1997).  
We incorporate the different elements of per-
sonal names (Figure 1) into a semantic network  
(Figure 2) to illustrate how they associate with 
each other, e.g. with hierarchies. 
Figure 2: Representation of the names elements using semantic nets 
88
Identifying and searching result in a list many 
names with variations and meanings. In order 
to find the correct person with a name we have 
to adopt ontologies of names, e.g. based on 
place of birth or relationship of people. The 
typical origins of surnames which can be a ba-
sis for ontologies of names can be classified as 
follows:
local surnames - surnames of relationship - 
surnames of occupation or office. 
Local surnames, which are most widely 
used, stem from toponyms, we can call them 
toponymic. They reflect land owners, place of 
birth, or the center of life. For example, Rich-
ard de Tonebridge was named after his castle 
of Tonbridge, but he was also called Richard 
de Clara from the Suffolk Clare, which became 
his chief seat and the family’s definitive sur-
name. Also Richard de Hadestoke, a London 
alderman, had left Hadstock (Essex) and set-
tled in London (Reaney and Wilson 1997). 
These local surnames derive (with occasional 
exceptions) from English, Scottish or French 
places (e.g. de, at, in). Toponymic Thai names 
are derived from Thai places and took origi-
nally a preposition na, for example, Prapas na 
Ranong is a person from a Southern province 
in Thailand called Ranong. 
Surnames which come from family relation 
are often called patronymic, but we have to 
introduce a more elaborate term, because we 
encounter names from females and other rela-
tions than just father, such as Gilbert Fatheved-
steppeson, Richard Hannebrothir, America 
Ibbotdoghter, and John Prestebruther.  
Surnames of occupation and office refer to 
actual office holders like clergy names or state 
offices. Some of these, such as steward, con-
stable, marshal, etc., became hereditary and 
gave rise to hereditary surnames, but the terms 
were also commonly used of lesser offices, 
whilst marshal was a common term for a far-
rier and such names frequently denoted the 
actual occupation. However, Nuns, Abbots, 
Priors, Monks and other clerical people were 
bound by vows of celibacy and thus did usu-
ally not have families which adopted their re-
spective surname. 
4 Rule Based Naming System for 
Thai Names 
In this section we introduce the well known 
methodology for Thai naming process as well 
as how Thai names can be constructed using 
the basic Thai rules of forming syllables. 
4.1 Custom Naming Process Using Thai 
Astrology
The way of naming can vary, e.g. naming by 
monks, grandparents. Since former times 
names are very important to people.  Naming 
from the past to the present has been continu-
ously developed and has developed a variety of 
patterns. Each pattern has it own rules depend-
ing on local places and the belief that has been 
developed until the present. The basic goal of 
naming is to provide a good fortune and pro-
gress during life. Most first names have a 
meaning. The widely used methodology of 
Thai naming process is briefly described in the 
following.
Principal naming using Thai astrology is 
widely used since the past. Because it uses the 
birth day to form the name. This is a belief that 
the individual has a set of 8 attributes called 
name of the angles referred to in Thai astrol-
ogy.  These attributes influence each person’s 
livelihood, fortune, etc. The attributes refer to 
Servant >Age> Power> Honour> Property> 
Diligence> Patron> Misfortune. Each attribute 
has it own letters which can be used for con-
structing names. 
4.2 Syllable Construction 
Syllables are aggregated to names which sound 
good or aimed at good fortune according to the 
methodology mentioned above. As a consonant 
can not stand alone in Thai language and per-
sonal names we consider rules for vowels only. 
The order is: 
Vowels can come first or can be followed 
by a first consonant, e.g. Ek 
Vowels can follow a first consonant with-
out a final consonant, e.g. Ka 
Vowels that can not have final consonant, 
e.g. Tam, Tua 
Vowels that need final consonant, e.g. Kak 
Figure 3: Forming of Thai syllables 
89
Example of construction of Thai syllables 
using Thai Romanization 1.10 unicode (CU 
2004) according to Figure 3:  � � (Ka)    = CV, 
 � � � (Ek)    = VC,  � � (Kok) = CF,  � � � (Kak) = 
CVF,  � � � (Ek) = VF. 
Thai names are built from one or more syl-
lables that may or may not have a meaning. 
There are syllables which alone do not mean 
much in particular, but when used as prefixes 
and suffixes can change the meaning of the 
syllables they precede  or follow as stated be-
low.
Prefixes: for example, (1) kob means 
"gather" while pra-kob means "put together" or 
"consist of", (2) cham means "remember" 
while pra-cham means "regularly". 
Suffixes: for example, (1) ngarm means 
"beautiful" and num means "water".  Add jai 
("heart") to each and we have names like 
ngarm-jai and num-jai meaning "beautiful in 
the heart" and "generous" respectively. 
In the following it is shown how to con-
struct Thai names that convey a meaning with 
the help of ontologies. Syllables are built from 
consonants (either C or F, C being the first and 
F the final consonant) and vowels. A name 
consists of one or more syllables. One syllable 
can have a meaning of its own, which leads in 
case of two or more syllables in a name to 
more complex meanings.  
The process of constructing names accord-
ing to the naming rules and methodology be-
gins with a leading consonant or vowel that 
can be the only letter in the name. If we con-
tinue to add more letters we come either to a 
valid name (a name which has a meaning) or to 
an invalid name (a name without a meaning). 
Invalid names will be discarded in such a way 
that the last letter will be replaced by another 
or will be added with more letters.  
Figure 4: Representation and construction 
of Thai names 
In Figure 4 it is shown that names comprise 
n syllables with a reasonable number of letters. 
The meanings of the syllables as well as of the 
name are found with the help of an ontology of 
names. 
The meaning of the name for a girl Pensri 
in the example (see Figure 4) is “the goodness 
and beauty of the moon”. 
How do we know which name belongs to a 
boy or a girl? There are several ideas to take 
into consideration when selecting a name for 
indicating the gender.  Ontologies can help in 
deciding the name by capturing and indexing 
the meaning as is shown in Table 1. 
Boys can be named by: 
 xtaking names of leading or important 
male characters accepted as having 
lasting literary value, e.g. Chakkri (an 
actor from KhunChang KhunPhaen) 
and Suthat (an actor from Phra Aphai 
Mani).
 xcombining monosyllables evidently 
indicating the males sex, e.g. Chatri (a 
mighty man), Choetchai (a perfect 
man), and Danai (son).
 xusing adjectives indicating male quali-
ties such as strength, and bravery, e.g. 
Watcharaphon (strength), woraphon 
(strength), and Kriangkrai (brevery) .    
 xusing terms representing something 
strong, important or high, e.g. Suriya, 
Phassakorn, and Phanuphong are 
popular names. They all mean the sun.  
Choosing names for girls is even more compli-
cated.  There are so many things to consider 
(Table 2).  A girl can be named by: 
 xtaking name of leading female charac-
ters from well-known literature: Phim 
Phi La Lai (an actress from Khun-
Chang KhunPhaen) and Suwanmali 
(an actress from Phra Aphai Mani).   
 xcombining monosyllables evidently 
indicating the females sex, e.g. Cha-
runi (pretty girl), Kanyarat (pretty 
woman), Khanitda (younger sister),and 
Khwansuda (beloved daughter).   
 xusing syllables indicating female quali-
ties such as those having to do with 
looks and beauty, e.g. Pariyaphat 
(lovely) and Phichittra (beautiful).  
90
 xusing syllables which are names of 
flowers, flowering trees: Manlika (jas-
mine), Maliwan (jasmine), and Wat-
sana (Charisma), all of which are 
names of flowers found in Thailand; 
also syllables which simply mean 
flower: Buppha, Phakamat, Butsabong, 
and Ladawan. 
 xusing syllables describing softness, 
gentleness and mildness, e.g. Pranit 
(gentle), Lamun (soft), and Sukhum 
(mild).  
 xusing syllables describing scent, taste, 
e.g. Saowakhon (lovely smell, fra-
grant) and Parimon (fragrant), 
Mathurot (sweet) and Wasita (sweet 
and aromatic). On the other hand, un-
favourable tastes like Khom (bitter) or 
Fad (sappy) are not used.   
 xusing syllables which are names of or-
naments and jewellery, e.g. Phatchara 
Walai (diamond bracelet), Rattana 
Wali (gem necklace), Phara (dia-
mond), and Rachawadi (blue gems). 
Table 1 Examples of Thai names with their meanings according to male gender. 
91
Table 2 Examples of Thai names with their meanings and female gender.
This grouping process is used to build an ontol-
ogy which has a (classified) database structure. 
This allows for speeding up the information re-
trieval process for the naming system.  
4.3 Web Based Naming Expert System 
Currently we are constructing and implementing 
a web-based naming expert system which offers 
two basic ways to come to “good” Thai names 
according to the first methodology mentioned 
above. The system will give us the letters for 
each date of birth. We use these letters to con-
struct names based on the basic rules (see Figure 
2). The user will be able to choose from a list of 
resulting possible names according to their re-
spective meaning. 
We use a dictionary database of more than 
8.000 Thai names which contains not only the 
spelling, but also the meaning and correct pro-
92
nunciation. In situations where names follow the 
rules but do not have a meaning we compare the 
name with similar names in a dictionary database 
and check for similarity using a simple string 
matching scheme. Then the user can select the 
best name from the resulting list of names. 
A second way to come to names is by using 
ontologies instead of basic spelling rules which 
are used according to the sex and date of birth. 
For this we check the different names against the 
date of birth by implementing an indexed data-
base system of names from Thai dictionary for 
every day of a week.  
5 Conclusion and Further Work 
We have used Thai customs for the naming proc-
ess, an ontology of names, and the basic rules for 
forming syllables in Thai to construct the rule 
based naming system. We want to extend the 
system using name matching algorithms to return 
the variants of names from a Thai dictionary with 
the relative probability of their similarity. To 
speed up this process we will use a database 
structure based on an ontology of names, e.g. by 
indexing names according to gender and mean-
ing with the help of a Thai dictionary database. 
We will use a Romanized version of Thai names. 
The advantage of this process would be an 
improvement of searching algorithms for Thai 
names in databases as well as in the internet. 
Here we will need name matching algorithms. 
The next step of development is to take into ac-
count different cultures.
Currently we are designing a system for mul-
ticultural name matching called NARESUAN-
M2 (NAme Recognition Expert System Using 
Automated Name Matching Methods). A pri-
mary objective here is to study how ontologies 
and algorithms can help in deciding which rules 
of naming system have to be implemented. This 
will also require an investigation into how on-
tologies that cover the different elements of 
names can be merged. 

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