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አማርኛ Vig, vigorish or juice is US betting slang for the bookmaker's commission — the same thing European bettors call margin or overround. It is not a line item on your slip; it hides inside prices that together imply more than 100% probability.
The classic American expression is -110/-110 on a point spread: bet 110 to win 100 on either side. Each side implies 52.4%, the pair sums to 104.8%, and the 4.8% is the vig.
Worked example
-110 both sides: implied 52.38% each, total 104.76%. A bettor picking spreads at random loses 4.76 cents per dollar staked in the long run — that is the vig doing its work, no bad luck required.