Definition
An electrical switch operated by turning a knob or shaft, with multiple fixed positions that each connect the input to a different output circuit. Common examples in aircraft include the magneto switch (OFF–R–L–BOTH–START) and avionics or fuel selector switches.
Plain English
A switch you turn instead of flip. Each position you click into sends power to a different circuit.
Context Anchor
Seen on aircraft panels and equipment where a pilot selects among several positions, such as OFF, LEFT, RIGHT, BOTH, or different light or system settings.
Derivation
From Latin rotare, meaning 'to turn.' The name describes how the switch works — you rotate it to select between positions.
Why Pilots Care
Allows compact control of multiple options without separate switches for each, reducing panel clutter and pilot workload.
Analogy
It is like the knob on a stove or fan: each click or position selects a different setting.
Intuition Check
Do not connect rotary here with a rotary engine. In this term, rotary simply means the switch is turned to select a position.
Example Sentence 1
The pilot moved the rotary magneto switch from BOTH to L and back, listening for the expected RPM drop.
Example Sentence 2
Before takeoff the rotary switch was rotated to the magneto test position.