Today's AU - Great Western Horse Racing Picks

Pari-Mutuel

A pool style wagering system, where all money input through betting is divided among those with winning tickets (save for various deductions by the track operators).

Bug

An apprentice jockey.

Tack

The equipment the horse wears, including saddle and bridle. A jockey typically has their own racing saddle, placed on each horse they ride just before the race.