Definition
A multi-position electrical switch designed so that the moving contact fully disconnects from the first terminal before it touches the next terminal. At no point during the transition is the switch connected to two terminals at once.
Plain English
A switch that lets go of one connection before grabbing the next one, so the two circuits are never linked together even for an instant.
Context Anchor
Seen in aircraft electrical, ignition, and avionics switch discussions where a switch selects between more than one circuit or source.
Derivation
The name describes the action in order: it 'breaks' (disconnects) the existing contact before it 'makes' (creates) the new one. This is the opposite of a 'make-before-break' switch, where the new connection forms first and the old one drops afterward.
Why Pilots Care
Prevents momentary short circuits that could damage avionics or create electrical hazards during power-source changes.
Intuition Check
“Break” does not mean the switch is damaged. “Make” does not mean it is being built. Here, they mean opening and closing an electrical path.
Example Sentence 1
The fuel quantity selector uses a break-before-make switch so that no two tank senders are ever connected to the gauge at the same time.
Example Sentence 2
During the preflight check the mechanic confirmed the break-before-make action on the selector switch.