What is a "prefix"?

A prefix is defined as a letter or group of letters added at the beginning of a word to change or enhance its meaning. This linguistic element can modify the word it precedes, often indicating a negation, reversal, or some other change in meaning. For instance, adding the prefix "un-" to the word "happy" transforms it to "unhappy," thus altering its meaning to signify a lack of happiness. This foundational aspect of vocabulary development helps with understanding the nuances of language and semantics, allowing for richer expression and comprehension in communication.

The other options describe different parts of speech or functions in language but do not accurately define what a prefix is. The second choice refers to nouns, the third choice specifies verbs, and the fourth choice describes adjectives, none of which convey the specific role of prefixes in word construction.