shutdown n.

Middle English shitten, sheten, "close (a door, window, gate, etc.); lock, fasten closed," from Old English scyttan "to put (a bolt) in place so as to fasten a door or gate, bolt, shut to; discharge, pay off," from West Germanic *skutjan (source also of Old Frisian schetta, Middle Dutch schutten "to shut, shut up, obstruct"), from PIE root *skeud- "to shoot, chase, throw." Related: Shutting.

The meaning "to close by folding or bringing together" is from mid-14c. That of "prevent ingress and egress" is from mid-14c. The sense of "to set (someone) free (from)," by c. 1500, is obsolete except in dialectal phrases such as get (or be) shut of (attested by 1570s). To shut (one's) mouth "desist from speaking" is recorded from mid-14c.

As a past-participle adjective, "made fast, closed, enclosed," by late 15c. As a noun, "action, time, or place of shutting," by 1660s.

"in a descending direction, from a higher to a lower place, degree, or condition," late Old English shortened form of Old English ofdune "downwards," originally of dune "off from (the) hill," from dune "from the hill," dative of dun "hill" (see down (n.2)). The "hill" word is general in Germanic, but this sense development is peculiar to English. As a preposition, "in a descending direction upon or along,"  from late 14c.

To be down on "express disapproval of" is by 1851. Down home is from 1828 as "in one's home region," as an adjective phrase meaning "unpretentious" by 1931, American English. Down the hatch as a toast is from 1931. Down to the wire is 1901, from horse-racing.

Down Under "Australia and New Zealand" attested from 1886; Down East "Maine" is from 1825; Down South "in the Southern states of the U.S." is attested by 1834. Down the road "in the future" is by 1964, U.S. colloquial. Down-to-earth "everyday, ordinary, realistic" is by 1932.