from
The Collaborative International Dictionary of English v.0.48
Horse-chestnut \Horse`-chest"nut\, Horsechestnut
\Horse`chest"nut\, n.
1. (Bot.) The large nutlike seed of a species of {Aesculus}
({Aesculus Hippocastanum}), formerly ground, and fed to
horses, whence the name. The seed is not considered edible
by humans. [WordNet sense 2]
[1913 Webster + WordNet 1.5]
2. (Bot.) The tree itself ({Aesculus hippocastanum}), which
was brought from Constantinople in the beginning of the
sixteenth century, and is now common in the temperate
zones of both hemispheres; it has palmate leaves and large
clusters of white to red flowers followed by brown shiny
inedible seeds. The native American species is also called
{buckeye} and {conker}. [WordNet sense 1]
[1913 Webster + WordNet 1.5]