A horse chestnut is a large tree which has leaves with several pointed parts and shiny reddish-brownnuts called conkers that grow in cases with points on them.
2. countable noun
Horse chestnuts are the nuts of a horse chestnut tree. They are more commonly called conkers.
horse chestnut in British English
noun
1.
any of several trees of the genus Aesculus, esp the Eurasian A. hippocastanum, having palmate leaves, erect clusters of white, pink, or red flowers, and brown shiny inedible nuts enclosed in a spiky bur: family Hippocastanaceae
2. Also called: conker
the nut of this tree
Word origin
C16: so called from its having been used in the treatment of respiratory disease inhorses
horse chestnut in American English
1.
any of a genus (Aesculus) of shrubs and trees of the horse-chestnut family, including buckeyes; esp., a tree (A. hippocastanum) with large, palmately compound leaves, clusters of white flowers, and glossy, brown seeds
2.
a seed of this tree
horse-chestnut in American English
(ˈhɔrsˌtʃɛsnʌt)
adjective
designating a family (Hippocastanaceae, order Sapindales) of dicotyledonous trees, includingthe horse chestnuts
Word origin
transl. of obs. botanical L Castanea equina: reason for name uncert.