/mä-lē-gärd/
[University of Illinois]
n. A shield to prevent tripping of some Big Red Switch by clumsy or ignorant hands. Originally used of some plexiglass covers improvised for the BRS on an IBM 4341 after a programmer's toddler daughter (named Molly) frobbed it twice in one day. Later generalized to covers over stop/reset switches on disk drives and networking equipment.