noun
crushed stone; hardcore; macadam
Abbreviation of 割栗石 (わりぐりいし). Used in civil engineering and construction for coarse broken stone used as a base layer or fill.
See also: 割栗石
道路の下に割栗を敷き詰める。
They spread crushed stone under the road.
Compound of 割り (wari, 'splitting') + 栗 (kuri, 'chestnut'), from the resemblance of the broken stones to chestnuts. The exact historical derivation is uncertain.