Bronto Bronto, an unofficial unit prefix, used to represent anything from 1015 to 1027 bytes, most often 1027 Bronto Software, a software company "Bronto-" a prefix used in the classification of many large animals, such as Brontosaurus or Brontotherium PSA Bronto (Russian: ПСА Бронто) Russian company for the production of special vehicles and SUVs. See also Bronte (disambiguation) Brontosaurus (disambiguation)