Underlay

A horse that is going off at lower odds than it deserves based on performance.

Bleeder

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

Fractions

The times recorded during the race; with timing starting just past the gate or when the gates open, then parroted for the quarter, half, three-quarters etc. Used as an indication of ability and speed.