What does "horse chestnut" mean?

Any of several tree species of genus Aesculus, especially Aesculus hippocastanum, common in temperate northern hemisphere.

What is a synonym for "horse chestnut"?

Common synonyms include: aesculus hippocastanum, buckeye, buckeyes, conker, ebony, nut.

Pronounced //ˌhɔɹs ˈtʃɛsnʌt//.

/ˌhɔɹs ˈtʃɛsnʌt/ noun

noun ·Rare ·Advanced level

Noun

1
Any of several tree species of genus Aesculus, especially Aesculus hippocastanum, common in temperate northern hemisphere.
2
tree having palmate leaves and large clusters of white to red flowers followed by brown shiny inedible seeds wordnet
3
The large nutlike seed of these trees.
4
the inedible nutlike seed of the horse chestnut wordnet

Translating obsolete Latin name Castanea equina.