Noun
(countable, obsolete) A pothole or similar break in a road's surface caused by rainwater washing away the surface of the road.
(countable) A breakwater.
(countable) A barrier built across a steeply sloping road or trail in order to direct the flow of water and prevent erosion.
(countable, more generally) Any artificially constructed system or device to halt the destructive flow of water.
(countable) The time elapsed from an underwater explosion or seismic event until the arrival of the resulting energy wave at a hydrophonic detector.
(uncountable) The formation of beads of water on a smooth surface, especially when used as an indicator of impurities on the surface.
(countable) A break in the smooth surface of a body of water, such as a ripple, whitecap, or the roughness that results from water flowing over an uneven surface.
Source: en.wiktionary.org