The Collaborative International Dictionary
Horse-chestnut \Horse`-chest"nut\, Horsechestnut \Horse`chest"nut\, n.
(Bot.) The large nutlike seed of a species of [AE]sculus ( [AE]sculus Hippocastanum), formerly ground, and fed to horses, whence the name. The seed is not considered edible by humans. [WordNet sense 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]
Douglas Harper's Etymology Dictionary
1590s, from horse + chestnut. A tree probably native to Asia, introduced in England c.1550; the name also was extended to similar North American species such as the buckeye. Said to have been so called because it was food for horses. The nut resembles that of the edible chestnut but is bitter to the taste.
Wiktionary
n. (alternative spelling of horse chestnut English)
Usage examples of "horse-chestnut".
The tall spinney of horse-chestnut trees, raucous with the calling of the rooks and rubbish-roofed with the clutter of their sprawling nests, was one of their familiar places.
There is a big horse-chestnut tree between their garden and ours, very useful for getting conkers out of and for making stuff to rub on your chilblains.
The horse-chestnut bourgeons burst their sheaths to spread into trefoils and flame-shaped leaves.
They had begun it there, under the drooping branches of a huge horse-chestnut tree, that had sheltered them from the noise and light of a nearby tavern.
At such times, I have liked to sit down on one of the empty benches in the Hof Garden, where the leaves already half cover the ground, and the dropping horse-chestnuts keep up a pattering on them.
Below him, Nicholas could see the horse-chestnut trees sheared into the shape of the letter 'L' at the four corners of the Place des Vosges.
Now only the iron gates flanked by rampant stone lions and the avenue of towering flat-bottomed horse-chestnuts, and the great house itself, square, yellowy-grey and Georgian, remained.
Sitting alone at night in his library, after the household had gone to bed, he had evoked the radiant outbreak of spring down the avenues of horse-chestnuts, the flowers and statues in the public gardens, the whiff of lilacs from the flower-carts, the majestic roll of the river under the great bridges, and the life of art and study and pleasure that filled each mighty artery to bursting.
On one of the upper balconies, which hung well above the rounded tops of the horse-chestnuts in the square, the awnings were still lowered, as though the sun had just left it.
No, what kept him in the city despite the increasing twisting inside that told him something was wrong back home, what kept him walking through the cold air breathed from the doors of movie houses and up and down between counters of perfumed lingerie thinking of all the delicate ass these veils would flavor the little tits to be tucked into these cups and jewelry and salted nuts poor old Jan and up into the park along paths he walked once with Ruth to watch from under a horse-chestnut tree five mangy kids play cat with a tennis ball and a broomstick and then finally back down Weiser to the drugstore he called from, what kept him walking was the idea that somewhere he’d find an opening.