pe·se·ta \pə̇ˈsād.ə, peˈ-, .sed.ə\noun (-s) Etymology: Spanish, diminutive of peso 1. a.: an old Spanish silver coin worth 1/4 of the piece of eight b.: a corresponding unit of value 2. a.: the basic monetary unit of Spain since 1868 — see money table b.: a coin or note representing this unit