What is the difference between an intertrip and an interlock.?

An intertrip will trip the system to prevent injury and could cause a lot of inconvenience, an interlock just prevents you doing something (like access) without tripping the system

That answer may be correct for switch gear in the UK, but the interlock on your microwave oven fits the description of inter trip better, as the microwave oven remains powered down until you close the door and reenter the cooking time and other options. This is also true of some other home appliances that have an interlock switch. Others resume operation when you close the door, so there is a third category that won't allow you to open the door if the circuits are energized. Likely there is some inconsistency in the use of the term interlock. Neil

As it says on the tin, an intertrip trips a device if operated and an interlock prevents two or more units operating at the same time.