noun, feminine/ˌpera ˈt͡ʃika/plural: perras chicas
5 céntimos coin
Literally, “small dog”. The 10 peseta céntimos and 5 peseta céntimos coins had a poorly drawn lion on their reverse, leading people to start calling the lion humorously a perra (she-dog). As the 5 céntimos coin was the smallest of both, the coin was called perra chica.