Pleonasm

Pleonasm (/ˈpliː.əˌnæzəm/; from Ancient Greek πλεονασμός (pleonasmós), from πλέον (pléon) 'to be in excess') is redundancy in linguistic expression, such as "black darkness" or "burning fire". It is a manifestation of tautology by traditional rhetorical criteria and might be considered a fault of style. Pleonasm may also be used for emphasis, or because the phrase has become established in a certain form. Tautology and pleonasm are not consistently differentiated in literature.