cat The collection of all members of the species Felis domesticus. Most members of this collection are #$DomesticCats, but feral cats are also included in this collection. Big cats, e.g., lions, ocelots, or tigers, are not members of this collection, although they are of its superset, #$FelidaeFamily. bd590573-9c29-11b1-9dad-c379636f7270