Love

What is love? From what the movies teach me is it - 1) Unexplainable pure and ideal as in twilight saga
2) Is it what the crew members felt for Martian
3) Is it just another name for lust?
4) Is it what Harry did even when he knew that it would lead to his death?
5) Is it just flirting?
6) Is it about having  someone always by your side - someone to count on someone to lean on?
7) Is it just... Well I don't know what it is yet for sure, all I know that at te it seems tougher than the toughest thing and at other its as easy as a rivers course you just flow with it naturally feeling light...