The Collaborative International Dictionary of English v.0.48:

Throb \Throb\, v. i. [imp. & p. p. Throbbed; p. pr. & vb. n.
   Throbbing.] [OE. [thorn]robben; of uncertain origin; cf.
   Russ. trepete a trembling, and E. trepidation.]
   To beat, or pulsate, with more than usual force or rapidity;
   to beat in consequence of agitation; to palpitate; -- said of
   the heart, pulse, etc.
   [1913 Webster]

         My heart
         Throbs to know one thing.                --Shak.
   [1913 Webster]

         Here may his head lie on my throbbing breast. --Shak.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Throb \Throb\, n.
   A beat, or strong pulsation, as of the heart and arteries; a
   violent beating; a papitation:
   [1913 Webster]

         The impatient throbs and longings of a soul
         That pants and reaches after distant good. --Addison.
   [1913 Webster]

WordNet (r) 3.0 (2006):

throb
    n 1: a deep pulsating type of pain
    2: an instance of rapid strong pulsation (of the heart); "he
       felt a throbbing in his head" [syn: throb, throbbing,
       pounding]
    v 1: pulsate or pound with abnormal force; "my head is
         throbbing"; "Her heart was throbbing"
    2: expand and contract rhythmically; beat rhythmically; "The
       baby's heart was pulsating again after the surgeon massaged
       it" [syn: pulsate, throb, pulse]
    3: tremble convulsively, as from fear or excitement [syn:
       shudder, shiver, throb, thrill]