A measurement of digital information storage or transmission, and a multiple of the unit "byte" and using the International System of Units prefix.
Terabytes are 2^40, which is equal to 1,099,511,627,776 bytes when in relation to computer memory like RAM.
The TB are also 10^12, or 1,000,000,000,000 bytes when in relation to storage solutions like flash drives or hard drives.
TB are one of the larger measures of byte multiples, and it is currently becoming the standard in home hard drive capacity. 1TB-3TB drives (until recently) could sell for under $120.
Very similar to Tebibytes, which use a more exact prefix established by the International Electrotechnical Commission.