The Collaborative International Dictionary of English v.0.48:

Mastic \Mas"tic\, n. [F., fr. L. mastiche, mastichum, Gr. ?, fr.
   ? to chew, because of its being used in the East for
   chewing.] [Written also mastich.]
   [1913 Webster]
   1. (Bot.) A low shrubby tree of the genus Pistacia
      (Pistacia Lentiscus), growing upon the islands and
      coasts of the Mediterranean, and producing a valuable
      resin; -- called also, mastic tree.
      [1913 Webster]

   2. A resin exuding from the mastic tree, and obtained by
      incision. The best is in yellowish white, semitransparent
      tears, of a faint smell, and is used as an astringent and
      an aromatic, also as an ingredient in varnishes.
      [1913 Webster]

   3. A kind of cement composed of burnt clay, litharge, and
      linseed oil, used for plastering walls, etc.
      [1913 Webster]

   Barbary mastic (Bot.), the Pistachia Atlantica.

   Peruvian mastic tree (Bot.), a small tree (Schinus Molle)
      with peppery red berries; -- called also pepper tree.

   West Indian mastic (Bot.), a lofty tree (Bursera
      gummifera) full of gum resin in every part.
      [1913 Webster]

WordNet (r) 3.0 (2006):

mastic
    n 1: an aromatic exudate from the mastic tree; used chiefly in
         varnishes
    2: a pasty cement used as an adhesive or filler
    3: an evergreen shrub of the Mediterranean region that is
       cultivated for its resin [syn: mastic, mastic tree,
       lentisk, Pistacia lentiscus]

U.S. Gazetteer Places (2000):

Mastic, NY -- U.S. Census Designated Place in New York
   Population (2000):    15436
   Housing Units (2000): 4732
   Land area (2000):     4.480560 sq. miles (11.604596 sq. km)
   Water area (2000):    0.339841 sq. miles (0.880183 sq. km)
   Total area (2000):    4.820401 sq. miles (12.484779 sq. km)
   FIPS code:            46074
   Located within:       New York (NY), FIPS 36
   Location:             40.802090 N, 72.843953 W
   ZIP Codes (1990):     11950
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Mastic, NY
    Mastic