text: how do i write a sentence using commas with appositive? what are appositve? in grammar, apposition is when you bring words or phrases together that are related. for example --  mr. keel, my son's geometry teacher, asked to meet with me next tuesday.   the phrase "my son's geometry teacher" is in apposition with mr. keel. it is an appositive. within my example is how to use the commas.