The Collaborative International Dictionary of English v.0.48:

Chico \Chi"co\, n.
   1. Var. of Chica.
      [Webster 1913 Suppl.]

   2. The common greasewood of the western United States
      (Sarcobatus vermiculatus).
      [Webster 1913 Suppl.]

   3. In the Philippines, the sapodilla or its fruit; also, the
      marmalade tree or its fruit.
      [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

Chico
    n 1: United States comedian; one of four brothers who made
         motion pictures together (1891-1961) [syn: Marx, Leonard
         Marx, Chico]