âºâº Definition: Terabyte A terabyte (commonly abbreviated TB) is a measurement term for data storage capacity. The number of bytes in a terabyte is sometimes stated to be approximately 1.0995 Ã 10 12. This difference arises from a conflict between the long standing tradition of using binary prefixes and base 2 in the computer world, and the more popular decimal (SI) standard adopted widely both within and outside of the computer industry.