CUCKOO-SPIT, CUCKOO-SPITTLE, noun A dew or exudation found on plants, especially about the joints of lavender and rosemary. Or a froth or spume found on the leaves of certain plants, as on white field-lychnis or catch-fly, called sometimes spatling poppy.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI