Your valentine is someone, for an example, someone u will love till grade school ends or just a friend, that you ask to be your valentines, or you get asked by that person or their grandma to be their valentine on 14th of February.
'' George'' is my valentine! We are gonna marry and have 20 kids!
Or as a friend
Me and ''JJ'' are gonna be each other's valentines cuz we both are ugly and can't handle a relationship!