What is a master set in Pokémon?

A master set is one copy of every card in a set, including every printing: normal, holo and reverse holo versions, plus the secret rares numbered above the printed total. A "regular" set usually means one of each card number.

Example from our data: Prismatic Evolutions has 180 card numbers but 280 priced printings. See master set costs for every set and the checklist guide.