1. To be stuck, incapable of proceeding without help. This is different from having crashed. If the system has crashed, it has become totally non-functioning. If the system is wedged, it is trying to do something but cannot make progress; it may be capable of doing a few things, but not be fully operational. For example, a process may become wedged if it deadlocks with another (but not all instances of wedging are deadlocks). See also gronk, locked up, hosed. 2. Often refers to humans suffering misconceptions. "He's totally wedged - he's convinced that he can levitate through meditation." 3. [Unix] Specifically used to describe the state of a TTY left in a losing state by abort of a screen-oriented program or one that has messed with the line discipline in some obscure way.
There is some dispute over the origin of this term. It is usually thought to derive from a common description of recto-cranial inversion; however, it may actually have originated with older "hot-press" printing technology in which physical type elements were locked into type frames with wedges driven in by mallets. Once this had been done, no changes in the typesetting for that page could be made.