The plural of suffix is suffixes.
A suffix is a linguistic element that is added to the end of a word to modify its meaning or create a new word. It is a type of affix used in many languages, including English. Suffixes can indicate different grammatical features, such as tense, number, gender, case, or they can change the word's part of speech. Examples of common suffixes in English include -s (indicating plural), -ed (indicating past tense), -ly (indicating adverb), and -able (indicating capable of). Suffixes play a significant role in word formation and can greatly impact the meaning and function of words.