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.

Nettle \Net"tle\, v. t. [imp. & p. p. {Nettled}; p. pr. & vb. n.
   {Nettling}.]
   To fret or sting; to irritate or vex; to cause to experience
   sensations of displeasure or uneasiness not amounting to
   violent anger.

         The princes were so nettled at the scandal of this
         affront, that every man took it to himself.
                                                  --L'Estrange.

Source : WordNet®

nettle
     v 1: sting with or as with nettles and cause a stinging pain or
          sensation [syn: {urticate}]
     2: cause annoyance in; disturb, especially by minor
        irritations; "Mosquitoes buzzing in my ear really bothers
        me"; "It irritates me that she never closes the door after
        she leaves" [syn: {annoy}, {rag}, {get to}, {bother}, {get
        at}, {irritate}, {rile}, {nark}, {gravel}, {vex}, {chafe},
         {devil}]

nettle
     n : any of numerous plants having stinging hairs that cause skin
         irritation on contact (especially of the genus Urtica or
         family Urticaceae)