gillyflower n.

before vowels kary-, word-forming element used since c. 1874 in biological terms referring to cell nuclei, from Greek karyon "nut, kernel," possibly from PIE root *kar- "hard," but Beekes leans toward the notion that it is a Pre-Greek word.

Proto-Indo-European root meaning "to thrive, bloom," possibly a variant of PIE root *bhel- (2) "to blow, swell."

It forms all or part of: blade; bleed; bless; blood; blow (v.2) "to bloom, blossom;" bloom (n.1) "blossom of a plant;" bloom (n.2) "rough mass of wrought iron;" blossom; cauliflower; chervil; cinquefoil; deflower; defoliation; effloresce; exfoliate; feuilleton; flora; floral; floret; florid; florin; florist; flour; flourish; flower; foil (n.) "very thin sheet of metal;" foliage; folio; folium; gillyflower; Phyllis; phyllo-; portfolio; trefoil.

It is the hypothetical source of/evidence for its existence is provided by: Greek phyllon "leaf;" Latin flos "flower," folio, folium "leaf;" Middle Irish blath, Welsh blawd "blossom, flower;" Gaelic bile "leaflet, blossom;" Old English blowan "to flower, bloom."

dried flowerbud of a certain tropical tree, used as a spice, late 15c., earlier clowes (14c.), from Anglo-French clowes de gilofre (c. 1200), Old French clou de girofle "nail of gillyflower," so called from its shape, from Latin clavus "a nail" (from PIE root *klau- "hook"). For second element, see gillyflower. The two cloves were much confused in Middle English. The clove pink is so called from the scent of the flowers.