cav·i·ty \ˈkavəd.ē, -ətē, -i\noun (-es) Etymology: Middle French cavité, from Late Latin cavitas hollowness, from Latin cavus hollow + -itas -ity — more at cave : a three-dimensional discontinuity in the substance of a mass or body : a space within a mass < a water-filled cavity in limestone > also: a space hollowed out (as by decay) < teeth full of cavities > < an old cavity excavated by a woodpecker — John Burroughs >