What is the term used for a word that has the opposite meaning?

The term used for a word that has the opposite meaning is "antonym." In language, antonyms are pairs of words that stand in contrast to each other, such as "hot" and "cold" or "happy" and "sad." This concept is foundational in understanding vocabulary and semantics, helping individuals express contrasting ideas more precisely.

Other related terms include synonyms, which refer to words that have similar meanings, anagrams, which are words formed by rearranging the letters of another word, and homonyms, which are words that sound the same or are spelled the same but have different meanings. Understanding these distinctions is important for effective communication and enhances one's comprehension of the nuances in language.