Alkanet, Alkanna tinctoria, a southern European plant with a root which is used to produce a red dye; the root of this plant or the dye (or other extract) itself. Occasionally also: any of various other plants of the genus Alkanna. Compare "alkanet", 2.
Late Middle English; earliest use found in Guy de Chauliac's Grande Chirurgie. From post-classical Latin alcanna henna, alkanet, in scientific Latin also (in form Alkanna) as genus name of the alkanet from colloquial Arabic al-ḥanna from al the + ḥanna, colloquial variant of literary Arabic ḥinnā').