Someone which causes sexual arousal or masturbatory desire. A person can become, or stop being, a source at any given time. From 'Curb Your Enthusiasm.'

To buy. To find. To acquire. To get.
Its current usage follows the modern fashion of using a noun as a verb.

A large, yet most desirable woman. She usually has an annoying voice and when her picture is taken her incredibly long tongue protrudes out of her gap toothed mouth.

Source is an extremely flexible/powerful video game engine developed by Valve Software, and it's primary use is for Half-Life 2, Counter-Strike: Source, and many Half-Life mods. But other games such as Vampires - Masqeurade: Bloodlines uses the same engine. It took Valve over 5 years of solid programming to develop Source.

Where something comes from. Commonly refers to source code, which is where applications come from.

Unnecessary change added to a good game.

Graphics and physics engine used in Half-Life 2 and Counter-Strike Source