sand boils

Noun

sand boil (plural sand boils)

1. An eruption of water through a bed of sand due, for instance, to seismic activity, or to differences in water pressure on two sides of a levee which causes water to penetrate beneath the levee.
   • "Whew!" said Tom, his eyes opening wide. "What must I do when I find a sand boil?" / "If you see a boil developing, grab a sack of dirt—we'll leave some at points a few hundred feet apart—put it right over the spout; pile on more as fast as you can and blow your horn for help, and keep blowing. We...1913 February, Garrard Harris, “Tom Ralston vs. The Mississippi: How One Boy Fought against Odds and Held in Check the Father of Waters”, in Boys' Life: The Boy Scouts' Magazine, volume II, number...
2. (rare) A boil which forms when sand particles enter and irritate the skin.
   • The boils called sand boils, which form on the front of the knee, are generally produced by small particles of sand being rubbed beneath the skin when the men are kneeling to holystone the decks. Very troublesome sores are thus produced. Great care should, therefore, be taken never to kneel with...1861, T[homas] Spencer Wells, “Boils”, in The Scale of Medicines with which Merchant Vessels are to be Furnished, by Command of the Privy Council for Trade; with Observations on the Means of...