bunker

What it means

1. governmentA hardened shelter, often partly buried or fully underground, designed to protect the inhabitants from falling bombs or other attacks.

   The military built a bunker to help evacuate the citizens safely from the bombings.

2. nauticalA compartment for storing coal for the ship's boilers; or a tank for storing fuel oil for the ship's engines.
3. rail transportThe coal compartment on a tank engine; it can also refer to that on a tender engine.

   The bunkers of these engines hold enough coal for one round journey of 120½ miles, and water is taken in each direction at Hexham.

   1941 December, “Notes and News: A Tank Engine's 241-mile Day”, in Railway Magazine, page 569

   2 more examples

   Among tank engines, the 0-6-2 wheel arrangement was by far the most numerous, there being nearly 450 of this arrangement, which offers the advantage of good power and adhesive weight, coupled with adequate tank and bunker capacity, within a limited compass.

   1939 September, D. S. Barrie, “The Railways of South Wales”, in The Railway Magazine, Westminster, London: IPC Transport Press, →ISSN, →OCLC, page 161

   The superstructure of the tender is modified by the removal of the side raves, and compartments for the fire-irons are formed on each side of the coal bunker.

   1956 April, “"Merchant Navy" Class Pacific Modified”, in Railway Magazine, page 212

In a sentence

The military built a bunker to help evacuate the citizens safely from the bombings.

Where it comes from

1. GermanBunker
2. Proto-Indo-European*bʰenǵʰ-“thick”
3. Proto-Germanic*bunkô“a heap, pile; a bump, lump, a crowd”
4. Old Norsebunki“a heap”
5. Early Scotsbunker
6. Scotsbunker“bench; pew; window-seat; sand pit (especially in golf); coal receptacle; sleeping berth, bunk”
7. Englishbunker

The origin of the noun is uncertain; the earliest sense is sense 7.1 (“box or chest, the lid of which serves as a seat”), from Scots bunker (“bench; pew; window-seat; sand pit (especially in golf); coal receptacle; sleeping berth, bunk”), from Early Scots bunker, bunkur, bonker (“a chest or box, often serving as a seat”), probably from Old Norse bunki (“a heap”) (probably whence bunk (“sleeping berth in a ship, train, etc.”)), from Proto-Germanic *bunkô (“a heap, pile; a bump, lump, a crowd”), perhaps from Proto-Indo-European *bʰenǵʰ- (“thick”) or *bʰeg- (“to billow, swell; to arch, bend, curve (?)”). Compare Middle Low German bunge (“drum, container”), Middle High German bunge (“drum”). Sense 1 (“hardened shelter designed to protect the inhabitants from falling bombs or other attacks”) was derived from German Bunker during World War II, which was itself from bunker (“large bin or container for storing coal”) (sense 5). The verb is derived from the noun.