WOW...DO NOT OPEN!

What makes someone your soul mate? Does it only apply to relationships, or can it apply to friendships as well? Maybe even someone in your family? And, lastly, does it indeed only have one, sole, individual meaning? 

I used to think the term “soul mate” was someone, anyone, who understood you like no one else could, and the same to you with them. If you were a puzzle, your soul mate would be the last piece, fitting perfectly into the middle to reveal a beautiful, collective picture.