tansy

Etymology

From Old French tanesie, tanoisie, tanasie, tanaisie, from Medieval Latin tanacetum, atanacetum, attested since the 8th century, of obscure origin, speculated from Ancient Greek ἀθανασία (athanasía, “immortality”) owing to hallucinations from the thujone in the plant, else from taenia (“tapeworm”) due to its primary use against parasites by which reason it is called in Arabic حَشِيشَة الدُود (ḥašīša ad-dūd, literally “worm herb”), otherwise a Berber borrowing like tagetes.

noun

1. A herbaceous plant with yellow flowers, of the genus Tanacetum, especially Tanacetum vulgare.
   Various measures were taken to avoid it, most popular being the suspension of certain herbs and tree branches over the doorways of dwellings and stables. Commonly used greenery were tansy, honesty, garlic, St. John's Wort, mountain ash, roadside verbena. 1940, Rosetta E. Clarkson, Green Enchantments: The Magic Spell of Gardens, The Macmillan Company, page 271
2. (uncountable, obsolete) A dish common in the seventeenth century, made of eggs, sugar, rose water, cream, and the juice of herbs (including tansy), baked with butter in a shallow dish. "Originally flavoured with tansy, but by Pepys's time generally having spinach as its predominant flavouring."
   I had a pretty dinner for them; viz., a brace of stewed carps, six roasted chickens, and a jowle of salmon, hot, for the first course; a tanzy and two neats' tongues, and cheese the second; and were very merry all the afternoon, talking and singing and piping upon the flageolette. 1662, Diary of Samuel Pepys