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.

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).

Across the Board

Refers to betting on a horse to finish first, second, and third to cover any of those scenarios happening during a race