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cuckoo-spit

[koo-koo-spit, koo k-oo-]
noun
  1. Also called frog spit. a frothy secretion found on plants, exuded by the young of certain insects, as the froghoppers, and serving as a protective covering.
  2. an insect that produces this secretion.

Origin of cuckoo-spit

1350–1400; Middle English cokkowespitle cuckoopint; so called from the spitlike secretion found on the plant and thought to be left by the bird
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for cuckoo spit

cuckoo spit

noun
  1. a white frothy mass on the stems and leaves of many plants, produced by froghopper larvae (cuckoo spit insects) which feed on the plant juicesAlso called: frog spit
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012