in botany, the sweet-smelling flag or calamus, a genus of the hexandria monogyne clasps. It is a native of this as well as other European countries. There are three varieties of this genus, viz. the acorus calamus; the vulgaris, or aromaticus of the shops; and the verus, which chiefly grows in the Indies.

in mat. med. a name sometimes given to the great galangal. See Galangal.

in botany, is likewise a synonyme of the iris pseudacorus. See Iris.