or·ris 
(ôrĭs, ŏr-)
(ôrĭs, ŏr-)n.
1. Any of several species of iris having a fragrant rootstock, especially Iris pallida and cultivars of the hybrid species I. ×germanica.
2. The fragrant rootstock of an orris, used chiefly in perfumes. Also called orrisroot.
[Probably alteration of Middle English yreos, from Medieval Latin, alteration of Latin īris; see IRIS.]