Althea \a-lthea, al-thea\ as a girl's name is pronounced al-THEE-ah. It is of Greek origin, and the meaning of Althea is "healing herb". From Althaia, and of a different root from Alethea. The name is derived from a shrub that is also called a marshmallow. Greek mythology: mother of Meleager. The name was revived in the 17th century by poet Richard Lovelace, as a poetic name for his beloved. Tennis celebrity Althea Gibson.