Odds On

Sometimes, horses are bet so heavily that they return less than $2 profit for each $2 wagered. These are called odds-on choices. For example, a horse that goes off at odds of 1-2 pays $1 for each $2 bet, plus your wager. Thus a $2 bet at 1-2 returns $1 + $2 for a total of $3. A winner at a payoff of under $4 is odds-on. Overlay - A horse whose odds in the actual wagering are greater than you think they ought to be; in other words, a horse you think is being overlooked by the public. The opposite is an underlay.

Amount you win is less than the amount you risk. Slang for "the favorite". A term usually associated with horse racing.