A forb or phorb is a herbaceous flowering plant that is not a graminoid (grass, sedge, or rush). The term is used in biology and in vegetation ecology, especially in relation to grasslands and understory.
"Forb" is derived from Greek phorb? (), meaning "pasture" or "fodder". The hellenic spelling "phorb" is sometimes used, and in older usage this sometimes includes graminids and other plants currently not regarded as forbs.
Forbs are members of a guild--a group of plant species with broadly similar growth form. In certain contexts in ecology, guild membership may often be more important than the taxonomic relationships between organisms.