Plain English Meaning
A device that senses temperature and turns something on or off, or opens or closes, to keep that temperature where it should be.
Full Definition
A temperature-sensitive control device that automatically opens or closes a valve, switch, or other actuator to maintain a system within a desired temperature range. In aircraft systems, thermostats are used to regulate engine oil temperature, cabin heat, carburetor air temperature, and similar heat-controlled circuits.
Context Anchor
Pilots may encounter thermostats in engine temperature control, oil or coolant systems, cabin heat systems, and other aircraft equipment that must stay within a safe temperature range.
Derivation
From Greek 'thermo' (heat) and 'statos' (standing or stationary). The original idea was a device that keeps heat 'standing still' — holding it steady at a chosen level.
Why Pilots Care
Maintains the engine within its safe operating temperature range, preventing overheating damage and supporting efficient performance.
Intuition Check
A thermostat is not the heater or cooler itself. It is the control that senses temperature and tells a valve or switch when to act.
Example Sentence 1
The oil cooler thermostat opens once the oil reaches operating temperature, allowing oil to flow through the cooler.
Example Sentence 2
Once the cylinder head temperature rose, the thermostat opened and allowed coolant to circulate through the radiator.