Accelerometer n. : An apparatus for measuring the velocity imparted by gunpowder.

Example:
How does the Accelerometer work on the ipod nano 4g?

Taxonomy
accelerometers, acceleration, measure, gravity, motion, orientation, measure gravity, vibration, reference frame, axis accelerometer, wilcoxon, mass, dome, recordings, camera, gravitational acceleration, proof mass, two-axis accelerometer.

Defination from the web:
accelerometer measures the acceleration it experiences relative to freefall. ... As a consequence, quite counter-intuitively, an accelerometer at rest on the Earth's surface will actually indicate 1 g upwards along the vertical axis. ...