Firewire is a registered trade name (Apple) used for the IEEE 1394 protocol standard. It is also used to describe the ports, connectors and cables used for this particular protocol. Since some companies don't want to pay a fee just to use the name, they've come up with their own.
Sony registered the name "iLink" while other camcorder manufacturers simply use "DV" (or DV I/O). Texas Instruments uses the name "Lynx."
No matter what name is used, they're all the same. Well, except for Canon. While the Firewire ports on a Canon camcorder are the same, they don't adhere very strictly to the IEEE 1394 protocol.
-DH