Webster's Revised Unabridged Dictionary · 1913

Althaa

Althaa ({not transcribed}) , noun

[althaea, Greek {not transcribed}.]

(a)
(Botany) A genus of plants of the Mallow family. It includes the officinal marsh mallow, and the garden hollyhocks.
(b)
(Botany) An ornamental shrub (Hibiscus Syriacus) of the Mallow family.

Also: Althea, Althaea