costmary
Concise Oxford English Dictionary © 2008 Oxford University Press:
costmary /ˈkɒstmɛːri/
▶noun (pl. costmaries) an aromatic plant of the daisy family, formerly used in medicine and for flavouring ale prior to the use of hops. [Balsamita major.]
– origin ME: from obs. cost (via L. from Gk kostos, via Arab. from Sanskrit kuṣṭha, denoting an aromatic plant) + Mary, the mother of Christ.
'costmary' also found in these Oxford entries:

