Drainage
来自Big Physics
Old English drēahnian, drēhnian ‘strain (liquid’), of Germanic origin; related to dry.
wiktionary
drain + -age
etymonline
drainage (n.)
1650s, "act or process of draining," from drain (v.) + -age. Sense of "the water carried off by a system of rivers" is by 1860. Meaning "system by means of which something is drained" is by 1878.
