Source : Webster's Revised Unabridged Dictionary (1913)

Nettle \Net"tle\, n. [AS. netele; akin to D. netel, G. nessel,
   OHG. nezz["i]la, nazza, Dan. nelde, n["a]lde, Sw. n["a]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 gracitis} is common in the Northern, and {U.
   cham[ae]dryoides} in the Southern, United States. the common
   European species, {U. urens} and {U. dioica}, are also found
   in the Eastern united States. {U. 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 {L. gigas} and {L. moroides}); -- also
      called {nettle tree}.

   {Bee nettle}, {Hemp nettle}, a species of {Galeopsis}. See
      under {Hemp}.

   {Blind nettle}, {Dead nettle}, a harmless species of
      {Lamium}.

   {False nettle} ({B[ae]hmeria 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}.

   {nettle tree}.
   (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} (Zo["o]l.), a medusa.



   {Dead letter}.
       (a) A letter which, after lying for a certain fixed time
           uncalled for at the post office to which it was
           directed, is then sent to the general post office to
           be opened.
       (b) That which has lost its force or authority; as, the
           law has become a dead letter.

   {Dead-letter office}, a department of the general post office
      where dead letters are examined and disposed of.

   {Dead level}, a term applied to a flat country.

   {Dead lift}, a direct lift, without assistance from
      mechanical advantage, as from levers, pulleys, etc.;
      hence, an extreme emergency. ``(As we say) at a dead
      lift.'' --Robynson (More's Utopia).

   {Dead line} (Mil.), a line drawn within or around a military
      prison, to cross which involves for a prisoner the penalty
      of being instantly shot.

   {Dead load} (Civil Engin.), a constant, motionless load, as
      the weight of a structure, in distinction from a moving
      load, as a train of cars, or a variable pressure, as of
      wind.

   {Dead march} (Mus.), a piece of solemn music intended to be
      played as an accompaniment to a funeral procession.

   {Dead nettle} (Bot.), a harmless plant with leaves like a
      nettle ({Lamium album}).

   {Dead oil} (Chem.), the heavy oil obtained in the
      distillation of coal tar, and containing phenol,
      naphthalus, etc.

Source : WordNet®

dead nettle
     n 1: foul-smelling perennial Eurasiatic herb with a green
          creeping rhizome [syn: {hedge nettle}, {Stachys
          sylvatica}]
     2: any of various plants of the genus Lamium having clusters of
        small usually purplish flowers with two lips
     3: coarse bristly Eurasian plant with white or reddish flowers
        and foliage resembling that of a nettle; common as a weed
        in United States [syn: {hemp nettle}, {Galeopsis tetrahit}]
     4: a plants of the genus Pilea having drooping green flower
        clusters and smooth translucent stems and leaves [syn: {richweed},
         {clearweed}, {Pilea pumilla}]