The Collaborative International Dictionary of English v.0.48:
Nettle \Net"tle\, n. [AS. netele; akin to D. netel, G. nessel,
OHG. nezz["i]la, nazza, Dan. nelde, n[aum]lde, Sw.
n[aum]ssla; cf, Lith. notere.] (Bot.)
A plant of the genus Urtica, covered with minute sharp
hairs containing a poison that produces a stinging sensation.
Urtica gracilis is common in the Northern, and Urtica
chamaedryoides in the Southern, United States. The common
European species, Urtica urens and Urtica dioica, are
also found in the Eastern united States. Urtica pilulifera
is the Roman nettle of England.
Note: The term nettle has been given to many plants related
to, or to some way resembling, the true nettle; as:
Australian nettle, a stinging tree or shrub of the genus
Laportea (as Laportea gigas and Laportea moroides);
-- also called nettle tree.
Bee nettle, Hemp nettle, a species of Galeopsis. See
Blind nettle, Dead nettle, a harmless species of
False nettle (Baehmeria cylindrica), a plant common in
the United States, and related to the true nettles.
Hedge nettle, a species of Stachys. See under Hedge.
Horse nettle (Solanum Carolinense). See under Horse.
(a) Same as Hackberry.
(b) See Australian nettle (above).
Spurge nettle, a stinging American herb of the Spurge
family (Jatropha urens).
Wood nettle, a plant (Laportea Canadensis) which stings
severely, and is related to the true nettles.
Nettle cloth, a kind of thick cotton stuff, japanned, and
used as a substitute for leather for various purposes.
Nettle rash (Med.), an eruptive disease resembling the
effects of whipping with nettles.
Sea nettle (Zool.), a medusa.