What is a syllable or word that comes before a root word to change its meaning called?

The term for a syllable or word that comes before a root word to alter its meaning is known as a prefix. Prefixes are an essential part of word formation in English, providing additional context or modifying the meaning of the root word they precede. For example, the prefix "un-" in "unhappy" conveys the opposite meaning of the root word "happy." This morphological element enables speakers and writers to expand vocabulary and convey more specific ideas.

Suffixes, on the other hand, are added to the end of a root word and modify the word in different ways, such as changing its tense or turning it into a different part of speech. Root words serve as the base of a word from which other forms can be created but do not themselves change meaning. Inflection refers to modifications made to a word to express different grammatical categories, such as tense or plurality, rather than altering the root's meaning. Hence, the correct term to describe a syllable or word that precedes a root word to change its meaning is a prefix.