A zettabyte is a unit for measuring an amount of computer data — an enormous one. Counting up the ladder you already know: kilobyte, megabyte, gigabyte, terabyte, then petabyte, exabyte, and then zettabyte. Each step is a thousand times the one before, so a zettabyte is a thousand exabytes, a million petabytes, a billion terabytes. Your laptop holds perhaps one terabyte; a zettabyte is a billion of those. Because of that size, nobody stores a zettabyte of anything. The word exists to talk about the whole world at once: how much data all humans create in a year, how much traffic crosses the entire internet. That is where you will meet it — in technology news, in reports, in phrases like 'the zettabyte era'. It is written ZB for short. One caution about the number: strictly, a zettabyte is 10 to the power 21 bytes, and there is a separate unit, the zebibyte (ZiB), for the power-of-two version. Ordinary writing ignores that difference, and honestly so does most of the industry.

皆位元組、ZB（資料量單位，等於十億 TB）