Metal Hydride - An intermetallic compound or alloy in which hydrogen has been absorbed; also, the negative electrode in a nickel-metal hydride battery.
Cycle Life - The number of cycles under specified conditions which are available from a secondary battery before it fails to meet specified criteria as to performance.
Capacity Retention (or Charge Retention) - The fraction of the full capacity available from a battery under specified conditions of discharge after it has been stored for a period of time.
Hourly Rate (also see C-Rate) - A discharge rate, in amperes, of a battery which will deliver the specified hours of service to a given cutoff voltage.
Voltage Depression - An abnormal drop in voltage below expected values during the discharge of a battery.
End Voltage (also see Cutoff Voltage) - The prescribed voltage at which the discharge (or charge, if end-of-charge voltage) of a battery may be considered complete.
Distortion (individual) - Ratio between the rms value of an nth order harmonic and the rms value of the fundamental.