What does post time mean in horse racing?

In horse racing, the post time is the time of day that a race is to be run.

Racing programs list an estimated post time for each race for the convenience of fans who want to know what time they need to go to the track or tune in on TV if they want to watch a certain race.

At the track, you will hear the announcer periodically reference an upcoming post time to alert fans that they need to head to the betting windows if they want to get a bet down on the race.