[ 'kɒstmɛ:ri ]
■ noun ( plural 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 kuṛṭha , denoting an aromatic plant) + Mary , the mother of Christ.