Question

A _____ is a group of letters that have a particular meaning which appears at the beginning of a word.

Answer 1

Im thinking it is a prefix. i may be wrong though

Answer 2

The correct answer is "prefix."

Thus, the complete sentence is:

A prefix is a group of letters that have a particular meaning which appears at the beginning of a word.

The prefixes are affixes that form words from a morpheme that precedes the radical. Thus, they modify their meaning but, generally, maintain the grammatical class to which they belong.