super bowl prop bet?

What does "prop" mean? Support?

Context:



http://www.docsports.com/superbowlprops.html

In most contexts, "proposition bet" denotes a bet made regarding the occurrence or non-occurrence during a game (usually a gambling game) of an event not directly affecting the game's final outcome.

Betting on which specific sub-outcomes occur during a game in which multiple sub-outcomes normally have the same value, for example:
Betting on the number of balls/strikes thrown by an American baseball pitcher, which is where the proposition bet was said to have originated.[2]
Betting on which team scores first in a match