noun
man-made water channel; artificial trench; moat
Archaic term for a man-made water channel, especially one dug around a castle for defense. Now mostly encountered in historical contexts.
城の周りには深い堀切が巡らされていた。
A deep moat was dug around the castle.
堀 is the common modern word for a moat or canal, while 堀切 is an archaic term for a specifically man-made trench or channel.
Compound of 堀 (hori, 'ditch, moat') and 切 (kiri, 'cut'), literally 'cut ditch'. The exact historical derivation is uncertain, but the term likely originated in castle construction terminology.