The Collaborative International Dictionary of English v.0.48:

Shepherd \Shep"herd\, n. [OE. schepherde, schephirde, AS.
   sce['a]phyrde; sce['a]p sheep + hyrde, hirde, heorde, a herd,
   a guardian. See Sheep, and Herd.]
   1. A man employed in tending, feeding, and guarding sheep,
      esp. a flock grazing at large.
      [1913 Webster]

   2. The pastor of a church; one with the religious guidance of
      others.
      [1913 Webster]

   Shepherd bird (Zool.), the crested screamer. See
      Screamer.

   Shepherd dog (Zool.), a breed of dogs used largely for the
      herding and care of sheep. There are several kinds, as the
      collie, or Scotch shepherd dog, and the English shepherd
      dog. Called also shepherd's dog.

   Shepherd dog, a name of Pan. --Keats.

   Shepherd kings, the chiefs of a nomadic people who invaded
      Egypt from the East in the traditional period, and
      conquered it, at least in part. They were expelled after
      about five hundred years, and attempts have been made to
      connect their expulsion with narrative in the book of
      Exodus.

   Shepherd's club (Bot.), the common mullein. See Mullein.


   Shepherd's crook, a long staff having the end curved so as
      to form a large hook, -- used by shepherds.

   Shepherd's needle (Bot.), the lady's comb.

   Shepherd's plaid, a kind of woolen cloth of a checkered
      black and white pattern.

   Shephered spider (Zool.), a daddy longlegs, or harvestman.


   Shepherd's pouch, or Shepherd's purse (Bot.), an annual
      cruciferous plant (Capsella Bursapastoris) bearing small
      white flowers and pouchlike pods. See Illust. of
      Silicle.

   Shepherd's rod, or Shepherd's staff (Bot.), the small
      teasel.
      [1913 Webster]

WordNet (r) 3.0 (2006):

shepherd dog
    n 1: any of various usually long-haired breeds of dog reared to
         herd and guard sheep [syn: shepherd dog, sheepdog,
         sheep dog]