Galvanometer
Definition
The ancestor of every analog meter — a tiny current twists a coil in a magnetic field, swinging a needle.
Technical definition
Torque τ = NIAB on the coil balances a spring, so deflection is proportional to current. With shunts or multipliers it becomes an ammeter or voltmeter.
Example
Vintage multimeters with swinging needles are galvanometers at heart — the needle's inertia even smooths out flickering readings.
Common confusion
A bare galvanometer can't directly measure volts or amps in a circuit — it is a delicate movement that must be adapted with shunt or series resistors for each job.