GB (Gigabyte) - definition Gigabyte is a unit to measure the size of certain data/file. Mathematically, 1GB=1024MB (Megabytes). Usually storages are measured in this scale, such as 500GB HDD, 250GB SSD. Related Terms:802.11acCMYKGbps (Gigabits per second)Memory card slotMicro USBUSB Type-C or USB-C