System operator. Written usually as "sysop" and pronounced sis as in "system" and op as in "operator" (go figure). The person in charge of a BulletinBoardSystem. Equivalent to "root" or "webmaster" of an Internet node, or vice versa depending on how you see it.

On WikiPedia, a SysOp is a user with the ability to delete pages, protect pages, or HardBan users.