1.noun. *Philosophy* - doctrine that advocates Riding -addressing perceived threats or slights with immediate physical confrontation and or reprisal to a degree greater than the original injustice, at *any* cost, since no cost is greater than death. To not address such threats with such speed or intensity is to die in that 1) Once the person or group or whoever threatened/slighted/dishonored/beat you, your friends or your community finds out that you or your group is hesitating in its self defense ('soft'), he or his group will take advantage of your weakness, making life worse, possibly unbearable. This is to be guarded against with unending vigilance. Think Live Free or Die. 2) For ride or die adherents, to be without honor is to be without life. As Joseph Addison once said, "Better to die 10,000 deaths than wound my honour.
2. Positive description of fraternal or romantic relationship partner(s) by virtue of one's willingness and commitment to do anything for them (represented by the word Ride), no matter the cost, and therefore to be stoppable only by death as represented by the word Die.
def 1. You are invited to a weekend party and told to bring friends. One of the friends you bring wears a shirt emblazoned with your school logo. The party you're going to is mostly attended by your school's main athletics competition. At the party, someone from that school delivers a severe beating to your innocent friend with the shirt just because of the shirt. By Monday, before lunch, ride-or-die adherents have a plan to punish the person who hurt your friend with damage and pain substantially but not grossly greater than he inflicted. At lunch, they do it. That is to ride. To not do it, to do anything but take care of it immediately, when all that matters is doing just that, is to die.
That is Ride or Die.
def 2. You love your romantic partner; if she needs something, you get it. The only way you could possibly not get it is when you die. So you Ride or Die.