An agreement or pact sworn upon by the hooking of pinkies of two or more participants. A pinky pact may also be called "pinky swear" or "pinky promise" by foolish, unpopular, and/or deprived youths.
Jeremy: "Ok, lets make a pinky pact that you will skype me this weekend."
Cynthia: "Its a 'pinky swear', no one says pinky pact."
Jeremy: "Maybe when you get some friends we can have this argument."