In vocabulary, what is an antonym?

An antonym is defined as a word that has the opposite meaning to another word. This concept is fundamental in understanding vocabulary, as it helps to recognize the contrast between different terms. For example, if the word "hot" is used, its antonym would be "cold," highlighting how antonyms are integral to grasping the breadth of meaning within a language. The other options address different linguistic concepts: synonyms refer to words with similar meanings, homonyms refer to words that sound the same but have different meanings, and nouns describe entities like people, places, or things. Thus, the distinction of antonyms as words with opposing meanings is what makes the correct choice clear.