Synonyms (in ancient Greek syn 'συν' = plus and onoma 'όνομα' = name) are different words with similar or identical meanings and are interchangeable. Antonyms are words with opposite or nearly opposite meanings (synonym and antonym are antonyms).

An example of synonyms are the words cat and feline. Each describes any member of the family Felidae. Similarly, if we talk about a long time or an extended time, long and extended become synonyms.

In the figurative sense, two words are often said to be synonymous if they have the same connotation:

"a widespread impression that … Hollywood was synonymous with immorality" (Doris Kearns Goodwin)

Synonyms can be nouns, adverbs or adjectives, as long as both members of the pair are the same part of speech.

More examples of English synonyms are:

• baby and infant (noun)
• student and pupil (noun)
• pretty and attractive (adjective)
• sick and ill (adjective)
• interesting and fascinating (adjective)
• quickly and speedily (adverb)

Note that the synonyms are defined with respect to certain senses of words; for instance, pupil as the "aperture in the iris of the eye" is not synonymous with student. Similarly, expired as "having lost validity" (as in grocery goods) doesn't necessarily mean death.

In English many synonyms are caused by the mixture of Norman French and English words, often with some words associated with the Saxon countyside ("folk": "freedom") and synonyms with the Norman nobility ("people": "liberty").

Some lexicographers claim that no synonyms have exactly the same meaning (in all contexts or social levels of language) because etymology, orthography, phonic qualities, ambiguous meanings, usage, etc. make them unique. However, many people feel that the synonyms they use are identical in meaning for all practical purposes. Different words that are similar in meaning usually differ for a reason: feline is more formal than cat; long and extended are only synonyms in one usage and not in others, such as a long arm and an extended arm. Synonyms are also a source of euphemisms.

The purpose of a thesaurus is to offer the user a listing of similar or related words; these are often, but not always, synonyms. In a way, hyponyms are similar to synonyms.

In contrast, antonyms (an opposite pair) would be:

• dead and alive (compare to synonyms: dead and deceased)
• near and far (compare to synonyms: near and close)
• war and peace (compare to synonyms: war and armed conflict)
• tremendous and awful (compare to synonyms: tremendous and remarkable)

External links

• Free Online English Thesaurus and Dictionary. Free Online English Thesaurus and dictionary containing synonyms, related Words, antonyms, definitions, idioms, words and terms using Merriam Websters Thesarus, Wordnet Reference and Roget's Thesaurus Definitions.
• Synonym tool for websites - creates lists of synonyms for arbitrary page on WWW
• English Synonym Dictionary - offers 500 searches for synonym per user per day
• Synonym Thesaurus