Entry 1 sense Webster, 1913 conker /(kŏṉk"ẽr)/ · conk·er · IPA /ˈkɒŋkə/ 01 n. the inedible nutlike seed of the horsechestnut. 1. the inedible nutlike seed of the horsechestnut. Syn. buckeye, horsechestnut, horse-chestnut.