HORNSTONE
Horn"stone`, n. (Min.)
Defn: A siliceous stone, a variety of quartz, closely resembling flint, but more brittle; — called also chert.
HORNTAIL
Horn"tail`, n. (Zoöl.)
Defn: Any one of family (Uroceridæ) of large hyminopterous insects, allied to the sawflies. The larvæ bore in the wood of trees. So called from the long, stout ovipositors of the females.
HORNWORK
Horn"work`, n. (Fort.)
Defn: An outwork composed of two demibastions joined by a curtain. It is connected with the works in rear by long wings.
HORNWORT
Horn"wort`, n. (Bot.)
Defn: An aquatic plant (Ceratophyllum), with finely divided leaves.
HORNWRACK
Horn"wrack`, n. (Zoöl.)
Defn: A bryozoan of the genus Flustra.