Pertaining or belonging to a colony: as, colonial government; colonial rights; specifically, in American history, relating to the thirteen British colonies which became the United States of America, or to their period. See colony.In zoology, forming colonies; consisting of or living as colonies; not separate; aggregative; social: as, the colonial Anthozoa.n. A member or citizen of a colony, especially of one of the British colonies in the eastern hemisphere.n. plural Colonial products, securities, etc.