Definition of ox-warble in US English:

ox-warble

noun

  • 1(More fully "ox-warble fly") either of two flies of the family Oestridae, Hypoderma bovis and H. lineatum, whose larvae live under the skin of cattle.

  • 2A swelling on the back of an ox caused by the larva of the ox-warble fly; the larva itself.

Origin

Mid 19th century; earliest use found in Jane Loudon (1807–1858), writer on botany and magazine editor.