Aces has been American slang for "the best" at least since the first years of this century, deriving from aces, the highest cards in poker and other card games. But ace for an expert combat flier who has shot down five or more enemy planes appears to have been borrowed from the French as, "ace," during World War 1. From there ace was extended to include an expert at anything. The card name ace comes ultimately from the Greek 'as, one.

Slang for asexual.

Anarcho-capitalism.

Also known as market anarchy or voluntarism/voluntaryism.

It's the idea that only voluntary cooperation (trade, the market) are legitimate forms of human interaction.

An anarcho-capitalist therefore envisions arbitration, security and defense to be solved through competing market agents instead of forceful territorial monopolists (as all statists including minarchists defend).

Alternating Current

This type of electrical current is called alternating because it switches direction. Direct current (DC) is often seen as the opposite of AC since DC only flows in one direction. Alternating current is used in most applications including the electricity that comes out of the outlet in your wall.

To pass a test or quiz. Often used in school.

When Playing Call of Duty or any other shooter is playing search and destroy. That one person kills all six enemies in one round.

Anti-chill; any behavior that completely violates the essence of chill.