marshmallow (n.) Look up marshmallow at Dictionary.com
Old English mersc-mealwe "kind of mallow plant (Althea officinalis) which grows near salt marshes;" from marsh + mallow. The confection (so called from 1877) originally was made from paste from the roots of this plant. The Greek word for the plant, althaea, is from althein, althainein "to heal, get well," from PIE root *al- (2) "to grow, nourish."