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Structure of a thesaurus

STRUCTURE OF Thesauruses

In Thesauruses, headwords or main entries are selected according to their frequency in the language. Each main entry is followed by:

  1. an abbreviation indicating the class of the word (vb for verb, n for noun, adj. for adjective, etc)
  2. a sense number (1, 2, etc to indicate the different senses of the word)
  3. a definition of the word
  4. one or more example sentences
  5. one or more sense groupings, i.e. sets of synonyms, so as to provide the user with a collection of words that are as close as possible in meaning to the headword.

Look at the entry for ‘quibble’ and notice how the information mentioned above is presented. The verbal illustration appears after the meaning core, i.e. the definition of the word, enclosed by angle brackets (). A list of synonyms indicated by boldface italic abbreviation syn follows.

quibble vb 1 to find fault with something usually on minor grounds <was a peevish critic, always ready to quibble>
 syn cavil, chicane, hypercriticise

In most Thesauruses, except for a list of synonyms, there are also lists of:

a) related words (words that are almost but not quite synonymous with the headword)

splendid adj extraordinarily or transcendently impressive
syn glorious, gorgeous, magnificent, proud, resplendent, splendiferous, splendorous, sublime, superb
rel eminent, illustrious ; grand, impressive, lavish, luxurious, royal, sumptuous ; divine, exquisite, lovely…

Note how related words are separated into subgroups by the use of semicolon (;).

b) idiomatic equivalents (phrases which are essentially the same in meaning as members of a synonym group)

speak  vb 1 to articulate words in order to express thoughts …
syn talk, utter, verbalize, vocalize, voice
rel …
idiom break silence, give voice to, let fall, make public (or known), open one’s mouth, put in words, say one’s say, speak one’s piece

In this entry, the idiom list (boldface abbreviation idiom) includes phrases that are generally pertinent to the entire synlist.

c) contrasted words (words that are strongly contrastable but not quite opposites of the headwords; boldface abbreviation con)

watchful adj paying close attention usually with a view to anticipating approaching danger or opportunity
con  inattentive, unmindful; aloof, detached, indifferent, unconcerned

Again, contrasted words are separated into subgroups that each share at least one aspect of contrast to the headword and its syn list.

d) Antonyms (opposites, boldface abbreviation ant)

assistance n 
syn help, aid, assist, comfort, hand, lift, relief, secours, succor, support
ant  impendiment, impeding; obstructing, obstruction

See how these are presented in the full entries for quibble’ and ‘calm’

quibble vb 1 to find fault with something usually on minor grounds quibble>
syn cavil, chicane, hypercriticise
rel carp, criticize
idiom split hairs
con applaud, commend, compliment, recommend; approve, endorse, sanction
calm adj 1 free from storm or rough activity < the wind died and the sea became calm> 
syn halcyon, hushed, placid, quiet, still, stilly, untroubled 
rel inactive, quiescent, reposing, resting; pacific, smooth, tranquil, unruffled 
idiom calm as a millpond, still as death 
con agitated, disturbed, perturbed, restless, turbulent, uneasy 
ant stormy

What do the abbreviations and symbols used stand for in this example entry? Do task 1 to familiarize yourselves with using a thesaurus. Write your answers in the space provided. Then go to ‘Key to Thesauruses and dictionaries’ and compare your answers with ours.

A word of caution about synonym lists

Each synonym listed within a given set should prove to be more or less substitutable for the main entry in the illustrative sentence. Yet, some judgment is required of the user in determining the syntax and idiomaticity with which a given word or expression can be substituted in an illustrative context; words are rarely as readily interchangeable in a context.

For this reason, synonyms should be cross-referenced, i.e. checked, before they are actually used. For instance, before deciding to use ‘halcyon’ instead of ‘calm’, we should check how ‘halcyon’ is used. Here is an entry for‘halcyon’:

halcyon adj joyful and carefree

It is obvious that ‘halcyon’ is not an ideal synonym to ‘calm’.


Use a thesaurus and find entries for the following headwords: placid and road. Then choose one synonym for each and check to what extent it is an ideal synonym.