The Collaborative International Dictionary of English v.0.48:

agar \a"gar\, n. [See agar-agar.]
   1. common shortened form of agar-agar[2].

   Syn: gelose, agar-agar.
        [PJC]

   2. 1 any culture medium that uses agar as the gelling agent;
      -- used especially with a modifying prefix, as, EMB agar.
      The term is applied both to the dehydrated medium powder
      containing agar and to the gelatinous medium prepared from
      it.

   Syn: nutrient agar
        [WordNet 1.5 +PJC]

The Collaborative International Dictionary of English v.0.48:

Agar-agar \A`gar-a"gar\, n. [Ceylonese local name.]
   1. A fucus or seaweed much used in the East for soups and
      jellies; Ceylon moss (Gracilaria lichenoides).
      [1913 Webster]

   2. A gelatinlike substance, or a solution of it, prepared
      from certain seaweeds containing gelose (such as Ceylon
      moss, Gracilaria lichenoides or other seaweeds of the
      genera Gelidium, Ceramium, Pterocladia, and
      Eucheuma), and used for solidifying growth media in the
      artificial cultivation of bacteria, or as a gelling agent
      in foods; -- usually called simply agar, by
      abbreviation.

   Note: In composition it is predominantly a polysaccharide,
         and is not degraded by most bacteria. It thus almost
         completely replaced the earlier protein-based gelatins
         used for fixing bacterial colonies on culture plates,
         as the gelatins were often dissolved by the proteolytic
         enzymes common in bacteria.

   Syn: gelose, agar.
        [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

agar
    n 1: any culture medium that uses agar as the gelling agent
         [syn: agar, nutrient agar]
    2: a colloidal extract of algae; used especially in culture
       media and as a gelling agent in foods [syn: agar, agar-
       agar]

Hitchcock's Bible Names Dictionary (late 1800's):

Agar, or Hagar, a stranger; one that fears


U.S. Gazetteer Places (2000):

Agar, SD -- U.S. town in South Dakota
   Population (2000):    82
   Housing Units (2000): 54
   Land area (2000):     0.168095 sq. miles (0.435364 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    0.168095 sq. miles (0.435364 sq. km)
   FIPS code:            00460
   Located within:       South Dakota (SD), FIPS 46
   Location:             44.838678 N, 100.072869 W
   ZIP Codes (1990):     57520
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Agar, SD
    Agar