One trillion bytes. Also TB, Tbyte and T-byte. See tera
and hard disk interfaces
A Terabyte of Portable Storage
Three Thousand Gigabytes
Although hard disks with a terabyte or more were already available, in 2013, Kingston Technology introduced the first terabyte USB drive. This is equivalent to 650,000 floppy disks, which was the common portable storage medium in the 1980s. Kingston subsequently came out with a 2TB USB drive. See USB drive
This three-terabyte hard drive is labeled 3,000 gigabytes. Why not "3TB?" Probably for continuity, because all previous drives were measured in GB. The 3,000 is also more impressive.