A synonym is a word that has the same or nearly the same meaning as another word in the same language. Synonyms are important for choosing the perfect word and for avoiding repetition in speech or writing. They can be any part of speech, including nouns, verbs, adjectives, adverbs, and prepositions. Synonyms are different words that have the same or similar meanings, and they come in every part of speech. The standard test for synonymy is substitution: one form can be replaced by another in a sentence without changing its meaning. For example, in the English language, the words begin, start, commence, and initiate are all synonyms of one another. Synonyms often express a nuance of meaning or are used in different registers of speech or writing. Different technical fields may appropriate synonyms for specific technical meanings. Some writers avoid repeating the same word in close proximity and prefer to use synonyms, which is called elegant variation.