1. To affix a prefix to something: Mrs. Smith told her student, Jill, that she would need to prepose "dis" to the word "cover" in order to create another word known as "discover".
2. To place a word, or words, before another one in a sentence: When writing a formal letter, be sure to prepose the title of the addressee correctly.
3. To make an advanced arrangement: Mr. and Mrs. Lawson's plans preposed Susan's suggestion that they go together to the ice rink the following day.