You can refer to someone, especially a man, as a giant, if they seem important or powerful or if they are big and strong. The biggest man in the patrol, a giant of a man, lifted Mattie on to his shoulders
Something that is described as giant is much larger or more important than most others of its kind. Italy's giant car maker, Fiat. a giant oak table. a giant step towards unification with the introduction of monetary union. = huge
A star that is considerably more luminous than a main sequence star of the same temperature (eg. red giant, blue giant)