AMA

The acronym for the American Motorcycle Association, a non-profit organization that does everything from sanction races to lobby the government for riders' rights.

The AMA generally has its heart in the right place, but it occasionally displays a certain favoritism to Harley-Davidson in its racing program that is both suspicious and annoying.

The outrigger part of an outrigger canoe. That is, a hollow, typically fiberglass, narrow, long thingie that runs parallel to the hull about 4-6 feet away from it, and is connected to the hull with two perpendicular iakos. This gives the canoe incredible stability, especially in waves. It's traditionally rigged to the left of the main hull. It's still possible to tip over, if you lean to the right! When the canoe becomes unsteady, you have to lean to the left to keep it from flipping over. If you rigged a canoe with two amas (one to each side), it would actually be less stable than a canoe with one ama. This is because with two hulls, they are always both contacting the water, but with three, it's possible to have the two amas contacting the water on wave peaks, with the hull suspended in the middle over a wave trough. This puts incredible stress on your rigging, and can cause nasty breakage. (Origin: Hawaiian.)

Beth

In the medical field it also stands for Against Medical Advice.
For example, if you happen to be in an MVA and the EMT's recommend you go to the hospital but you refuse, you can be sure their paperwork will have the sentence "Refused transport AMA" and you'll have to sign it so they don't get sued.