A roommate or housemate that has become more than just someone you live with by actually evolving into one of your friends.
Yeah man, I can't go out to the bar with you tonight, I'm chillin' with my friendmate.
by Immy1987 September 16, 2007
A soul-mate in friend form.
Susie: Hey Mary. You're like, my soul-mate in friend form. You're my FRIENDMATE. <3
by rachflam April 15, 2010