The Collaborative International Dictionary of English v.0.48:

Apiaceae \Apiaceae\ prop. n.
   A natural family of plants bearing flowers in umbels;
   examples are: parsley; carrot; anise; caraway;
   celery; dill.

   Syn: Umbelliferae, family Umbelliferae, family Apiaceae,
        carrot family
        [WordNet 1.5]

The Collaborative International Dictionary of English v.0.48:

Carrot \Car"rot\, n. [F. carotte, fr. L. carota; cf. Gr. ?]
   1. (Bot.) An umbelliferous biennial plant (Daucus Carota),
      of many varieties.
      [1913 Webster]

   2. The esculent root of cultivated varieties of the plant,
      usually spindle-shaped, and of a reddish yellow color.
      [1913 Webster]

WordNet (r) 3.0 (2006):

carrot
    n 1: deep orange edible root of the cultivated carrot plant
    2: perennial plant widely cultivated as an annual in many
       varieties for its long conical orange edible roots; temperate
       and tropical regions [syn: carrot, cultivated carrot,
       Daucus carota sativa]
    3: orange root; important source of carotene
    4: promise of reward as in "carrot and stick"; "used the carrot
       of subsidized housing for the workers to get their vote";