(1):

(a.) Having the limb of a tubular corolla or calyx divided into two unequal parts, one projecting over the other like the lips of a mouth, as in the snapdragon, sage, and catnip.

(2):

(n.) A plant of the order Labiatae.

(3):

(a.) Belonging to a natural order of plants (Labiatae), of which the mint, sage, and catnip are examples. They are mostly aromatic herbs.

(4):

(v. t.) To labialize.