Bleeder

A horse that bleeds due to a ruptured blood vessel during a race or workout. The medication Lasix can fix this problem.

Bute

Shortened word for phenylbutazone, the common non-steroidal medication legal at most racetrack.

Also Eligible

A horse that is entered but does not draw into the body of the field due to too many entries, and thus is not permitted to start unless there are enough scratches to shrink the field size.