A dictionary is a collection of words along with their meaning, definition and description of usage. A thesaurus presents words as "word families," listing their synonyms without explaining their meanings or usage. Thesauri may list words alphabetically or conceptually.

Comparison chart

Dictionary versus Thesaurus comparison chart
Edit this comparison chartDictionaryThesaurus
Description Collection of words in one or more specific languages listed alphabetically, which provides the meanings, definitions, etymologies and pronunciations of words. A book that lists words grouped together according to similarity of meanings or synonyms and sometimes antonyms.
World's first Much debate over the world's first dictionary. 2300 BCE in modern Syria or 3rd century BCE from China. Most trusted dictionary; Oxford English Dictionary published in full in 1884 as small books and in full after 50 years in 1928. The first modern English thesaurus created by Peter Mark Roget published in 1852.
Word Order A dictionary lists words alphabetically. A thesaurus may list words alphabetically or conceptually.
Word numbers Oxford English Dictionary lists about 500,000 words and a further half a million technical and scientific terms. Largest thesaurus contains more than 920,000 words.
Categories There are specialized dictionaries such as for science or business. Special thesauri are developed for information retrieval in information and science systems: a controlled vocabulary for indexing or tagging purposes.

Uses and coverage

'Word famillies in a thesaurus
'Word famillies in a thesaurus

A dictionary is used to look up the meaning of a particular word, say when want to know what a word means, or the various contexts in which it may be used differently, what part or parts of speech it is, etc. A dictionary gives thorough details on the meaning, definition, usage and etymology of a word.

A dictionary entry with definition, pronunciation, part of speech and other details
A dictionary entry with definition, pronunciation, part of speech and other details

A thesaurus usually does not contain all the words of the language. It provides several similar alternative words (synonyms), as well as contrasting words (antonyms). A thesaurus is also a useful resource when you know the meaning of the word but not the word itself.

Visual Thesaurus

This video explains how to use [www.visualthesaurus.com Visual Thesaurus] as a dictionary and a thesaurus:

Popular Publishers

The most popular dictionaries are Oxford English Dictionary, Chambers, Merriam-Webster and Collins.

The most popularly used thesaurus is Roget, and often Webster.


Much debate and doubt is cast over what constitutes as the world's first dictionary. Archaeologists have found a dictionary from the Akkadian Empire located in modern Syria of 2300 BCE, which contains bilingual word lists. A 3rd century Chinese dictionary was discovered as the first monolingual word list. Arabic dictionaries were complied in rhyme order in the 8th and 14th centuries. The earliest English dictionaries were bilingual glossaries in French, Italian or Latin. The first purely English alphabetical dictionary was written in 1604 by school teacher Robert Cawdrey called A Table Alphaeticall. It was not thought to be very accurate. Samuel Johnson's A Dictionary of the English Language was regarded as the most trusted 'modern' dictionary for around 150 years from 1755 until Oxford English Press released the Oxford English Dictionary 1884 in small books with a full complete version coming out 50 years later in 1928. It is now considered to be the most trusted dictionary in the world.

In antiquity Philo of Byblos wrote the first text that could be now thought of as a thesaurus. In Sanskrit the Amarakosha is a thesaurus in verse form, written in the 4th century. The first example of the modern genre, Roget's Thesaurus was compiled in 1805 by Peter Mark Roget and published in 1852. Entries in Roget's Thesaurus are listed conceptually rather than alphabetically.



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