The Collaborative International Dictionary of English v.0.48:

Hatchet \Hatch"et\ (-[e^]t), n. [F. hachette, dim. of hache ax.
   See 1st Hatch, Hash.]
   1. A small ax with a short handle, to be used with one hand.
      [1913 Webster]

   2. Specifically, a tomahawk.
      [1913 Webster]

            Buried was the bloody hatchet.        --Longfellow.
      [1913 Webster]

   hatchet face, a thin, sharp face, like the edge of a
      hatchet; hence:

   hatchet-faced, sharp-visaged. --Dryden.

   To bury the hatchet, to make peace or become reconciled.

   To take up the hatchet, to make or declare war. The last
      two phrases are derived from the practice of the American
      Indians.

WordNet (r) 3.0 (2006):

hatchet
    n 1: weapon consisting of a fighting ax; used by North American
         Indians [syn: tomahawk, hatchet]
    2: a small ax with a short handle used with one hand (usually to
       chop wood)

Moby Thesaurus II by Grady Ward, 1.0:

57 Moby Thesaurus words for "hatchet":
   adz, ax, battle-ax, bread knife, bushwhacker, butcher knife,
   carving knife, chaser, chisel, cleaver, clipper, clippers, dagger,
   gouge, hack, halberd, hoe, hunting knife, jackknife, knife, lance,
   lancet, letter-opener, machete, mattock, nippers, paper cutter,
   paper knife, paring knife, penknife, pick, pickax, plowshare,
   poleax, razor, razor blade, saw knife, sax, scalpel, scissors,
   scoop, scraper, scuffle hoe, scythe, share, shears, sheath knife,
   sickle, sidecutters, snips, spear, spokeshave, surgical knife,
   sword, table knife, tomahawk, wedge



The Devil's Dictionary (1881-1906):

HATCHET, n.  A young axe, known among Indians as a Thomashawk.

    "O bury the hatchet, irascible Red,
    For peace is a blessing," the White Man said.
        The Savage concurred, and that weapon interred,
    With imposing rites, in the White Man's head.
                                                           John Lukkus