exabyte /ˈɛksəbaɪt/ noun2 •One quintillion (10¹⁸, or 1,000,000,000,000,000,000) bytes or 1,000 petabytes.Altogether, the human brain is estimated to hold something in the order of 200 exabytes of information. — 2019 •(informal) An exbibyte. formsexabytes