synonym

n. Two words with similar or identical meanings are synonyms. For example, volume and tome are synonyms for the word book; student and disciple are synonyms for the word pupil. Arguably, details of the origins of words, as well as their additional senses (e.g., book can be a noun or a verb; pupil can refer to a student or to the opening in the iris of the eye), mean that no two words can be perfectly synonymous. Additional terminology provides more detailed ways for describing relations between words with similar meanings. For instance, plant is a hypernym for flower (or tree, bush, etc.) and tulip (or rose, dahlia, etc.) is a hyponym to flower. – EMF

▶ See also HOMOGRAPH