noun (plural costmaries)
- an aromatic plant of the daisy family, formerly used in medicine and for flavouring ale prior to the use of hops. Also called alecost.
- Balsamita major, family Compositae
late Middle English: from obsolete cost (via Latin from Greek kostos, via Arabic from Sanskrit kuṣṭha, denoting an aromatic plant) + Mary, the mother of Christ (with whom it was associated in medieval times because of its medicinal qualities)