noun

• Any of several species of trees of the genus Aesculus.
• Aesculus hippocastanum, the horse chestnut.
• Any of several species of the related Mexican buckeye (genus Ungnadia).
• The seed or fruit of these plants.
• (US, slang) A native or resident of the American state of Ohio.
• The Junonia coenia butterfly.
• (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.
• A native or resident of the American states of Ohio and Arizona.
• A number of places in the United States:
• A city in Maricopa County, Arizona.
• An unincorporated community in El Dorado County, California.
• A former travel station in Plumas County, California.
• An unincorporated community in Yolo County, California, named for buckeye trees there.
• Former name of Carbondale, Amador County, California.
• An unincorporated community in Larimer County, Colorado.
• An unincorporated community in Salamonie Township, Huntingdon County, Indiana.
• A minor city in Hardin County, Iowa.
• An unincorporated community in Dickinson County, Kansas.
• An unincorporated community in Garrard County, Kentucky.
• An unincorporated community in Mississippi County, Missouri, named for buckeye trees.
• An unincorporated community in Milton Township, Jackson County, Ohio, named after the Buckeye Furnace.
• An unincorporated community in Spokane County, Washington, named after the Buckeye Lumber Co.
• An unincorporated community in Pocahontas County, West Virginia, named after Buckeye Cove.
• A number of townships in the United States, listed under Buckeye Township.