SearchNetworking.com | Glossary | Definition – Kilo, mega, giga, tera, peta, and all that: Chris and I got to talking the other day about file sizes. You have kilobyte, megabyte, gigabyte, then terabyte. What’s next? Google to the rescue — the next four are petabyte, exabyte, zettabyte, and yottabyte. Now you know.