Definition of surface blow in English:

surface blow

noun

  • 1Engineering
    A device by which the surface water and scum in a steam boiler may be blown off.

  • 2A blow occurring when a whale is at the surface.

  • 3Metallurgy
    A defect in metal in the form of a small cavity on the surface of a casting.

Origin

Mid 19th century; earliest use found in United States Nautical Magazine & Naval Journal.