Hop, n. [OE. hoppe; akin to D. hop, hoppe, OHG. hopfo, G. hopfen; cf. LL. hupa, W. hopez, Armor. houpez, and Icel. humall, SW. & Dan. humle.] 1. (Bot.) A climbing plant (Humulus Lupulus), having a long, twining, annual stalk. It is cultivated for its fruit (hops).
2. The catkin or strobilaceous fruit of the hop, much used in brewing to give a bitter taste.
3. The fruit of the dog-rose. See Hip.
Hop back. (Brewing) See under 1st Back. — Hop clover(Bot.), a species of yellow clover having heads like hops in miniature (Trifolium agrarium, and T. procumbens). — Hop flea(Zoöl.), a small flea beetle (Haltica concinna), very injurious to hops. — Hop fly(Zoöl.), an aphid (Phorodon humuli), very injurious to hop vines. — Hop froth fly(Zoöl.), an hemipterous insect (Aphrophora interrupta), allied to the cockoo spits. It often does great damage to hop vines. — Hop hornbeam(Bot.), an American tree of the genus Ostrya (O. Virginica) the American ironwood; also, a European species (O. vulgaris). — Hop moth(Zoöl.), a moth (Hypena humuli), which in the larval state is very injurious to hop vines. — Hop picker, one who picks hops. — Hop pole, a pole used to support hop vines. — Hop tree(Bot.), a small American tree (Ptelia trifoliata), having broad, flattened fruit in large clusters, sometimes used as a substitute for hops. — Hop vine(Bot.), the climbing vine or stalk of the hop.