1. any of various tropical American plants of the genus Tagetes widely cultivated for their showy yellow or orange flowers
The Collaborative International Dictionary of English v.0.48:
Marigold \Mar"i*gold\, n. [Mary + gold.] (Bot.)
A name for several plants with golden yellow blossoms,
especially the Calendula officinalis (see Calendula), and
the cultivated species of Tagetes.
Note: There are several yellow-flowered plants of different
genera bearing this name; as, the African marigold or
French marigold of the genus Tagetes, of which
several species and many varieties are found in
gardens. They are mostly strong-smelling herbs from
South America and Mexico: bur marigold, of the genus
Bidens; corn marigold, of the genus Chrysanthemum
(Chrysanthemum segetum, a pest in the cornfields of
Italy); fig marigold, of the genus
Mesembryanthemum; marsh marigold, of the genus
Caltha (Caltha palustris), commonly known in
America as the cowslip. See Marsh Marigold.
Marigold window. (Arch.) See Rose window, under Rose.
WordNet (r) 3.0 (2006):
n 1: any of various tropical American plants of the genus
Tagetes widely cultivated for their showy yellow or orange