cat's-tail I. \ˈ ̷ ̷ˌ ̷ ̷\noun alsocat's-tail grass (pluralcats'-tails) Etymology: Middle English cattestail, a kind of plant, probably mullein, from cattes (gen. of cat) (I) + tail : any of several grasses of the genus Phleum; especially: timothy II. variant of cattail