A bet that is placed far in advance of an event happening. This usually means more than a week before the events happens. If the team/individual does not take part in the contest, you lose your money anyway. The equivalent of the futures market for stocks.
Bets placed in advance predicting the outcome of a future event. Ante-post prices are those on major sporting events, usually prior to the day of the event itself. In return for the chance of better odds, punters risk the fact that stakes are not returned if their selection pulls out or is cancelled.
Placing a bet for on a future event, usually the day before the event in question. The Ante Post offers better odds at the risk of the wager will be considered no action if the team or competitor is scratched or cancelled.