Definition of "buckeye"

buckeye

/ˈbʌkaɪ/

noun
plural buckeyes
1. Any of several species of trees of the genus Aesculus.
  1. Aesculus hippocastanum, the horse chestnut.
2. Any of several species of the related Mexican buckeye (genus Ungnadia).
3. The seed or fruit of these plants.
  Quotations
  Now there were long periods when he heard nothing except the wind in the trees and the plop of buckeyes on the earth.
  1973, Toni Morrison, Sula, Chatto & Windus (1993), page 155
4. (US, slang) A native or resident of the American state of Ohio.
5. The Junonia coenia butterfly.
6. (US) A confection made from peanut butter fudge partially dipped in chocolate to leave a circle of peanut butter visible, supposed to resemble the nut of the Ohio buckeye tree.