Defn: Any very hard rock.

IRIAN
I"ri*an, a.

Defn: Of or pertaining to the iris. "Irian nerves." Dunglison.

IRICISM
I"ri*cism, n.

Defn: Irishism. [R.] Jeffrey.

IRIDACEOUS; IRIDEOUS
Ir`i*da"ceous, I*rid"e*ous, a. Etym: [From NL. Iris, Iridis, the
Iris.] (Bot.)

Defn: Pertaining to, or resembling, a large natural order of endogenous plants (Iridaceæ), which includes the genera Iris, Ixia, Crocus, Gladiolus, and many others.

IRIDAL
I"ri*dal, a. Etym: [L. iris, iridis, rainbow. See Iris.]

Defn: Of or pertaining to the iris or rainbow; prismatic; as, the iridal colors. Whewell.

IRIDECTOMY
Ir`i*dec"to*my, n. Etym: [Gr. (Surg.)