I have absolutely no clue. I don't want to get technical here... i can though,
Hm, i guess it is the state of mind in which you care greatly for someone, for their looks, how they do things, how they act, how they treat people (or you), or however smart they are, and etc, usually of the different sex. That is, unless it is family members, but you "love" them for all of the same reasons. However, it is outside the family and of different sex (usually), then you would love them for all of those reasons i stated. You could technically "love" the person of the same sex (as if they were a good friend, etc), but you don't mean it in a sensual or affectionate way.
However, if it is in a sensual/affectionate/(insert some word here, i ran out of ideas), hopefully towards a different sex, then you could "love" them, that is if you want to "be with" that person for the rest of your life.
That's all i can think of.
yes, this practically sums up what i said, you could say.