The compound noun "stop-gap" is a transparent English formation from the late 15th century, combining the verb "stop" and the noun "gap." It originates from the literal, physical sense of stopping or plugging a hole in a barrier. The core logic is one of immediate, practical intervention: a "gap" represents a breach, lack, or deficiency, and to "stop" it is to halt its negative effects. Over time, this concrete imagery evolved into the modern abstract meaning, where any temporary measure designed to address a shortage or problem (such as a personnel vacancy or a systemic flaw) is metaphorically understood as something that plugs a leak until a proper repair can be made.

Structure: stop (to block) + gap (an opening) stop: From Old English stoppian (to block, close an opening), of West Germanic origin. Its functional role is the action taken. gap: From Old Norse gap (an opening, chasm). Its functional role is the problem or deficiency being addressed.