Which of the following best defines an acronym?

• A. A word formed by combining two or more words.
• B. A word that rhymes with another.
• C. A word that has the opposite meaning.
• D. Words formed from the first letter of a series of words.

Answer: (D)

An acronym is a new word created from the initial letters of the words in a phrase. The letters come from the first word of each part of the phrase, and together they form a single, pronounceable unit. For example, NASA comes from National Aeronautics and Space Administration, and scuba comes from Self-Contained Underwater Breathing Apparatus. The important idea is that the term is built from the initials of a longer name or description.

The other ideas describe different things: a word formed by combining two or more words is a compound word, a word that rhymes with another is about sounds, and a word with the opposite meaning is an antonym.