What does Ciaffone mean by overlay?

[Jay36489]

He seems to use it to mean advantage or to be favored, but I'm not sure if I'm missing something here.

Examples:
RE: Tourney section
"One fact about hold'em that is of critical importance for the late stages of satelite play is that it is hard to get a large overlay before the flop. Pair over Pair and suchlike is rare."

RE: Shorthanded
"The most important factor is who the other people that are in the game. If they are inferior players, you have a bigger overlay then in a full game."

Does it just mean your advantage or a situation that is positive EV?