The term "post-fix" refers to a word or morpheme that comes after the root or stem of a word to modify its meaning. Synonyms for this term include suffix, affix, addendum, ending, tail, and conclusion. These words are often used interchangeably when describing the structure of a word and its components. They all serve to alter the meaning of a term, expanding its definition or qualifying it further. Beyond these synonyms specific to morphology and grammar, other related terms might include supplement, complement, continuation, or appendix, each of which adds something extra or extends beyond the original.