The vibration monitoring industry has specialized jargon that is commonly used when talking about vibration sensors, accelerometers and associated applications. It's important that you understand common terminology to communicate effectively with vibration monitoring, reliability, condition monitoring and process automation professionals. We hope you find our glossary useful to find specialized terms and definitions used across vibration, condition monitoring and predictive maintenance.



An ideal shock pulse for which the acceleration-time relation has the shape of the positive (or negative) section of one cycle of a sine wave.


A sinusoidal quantity having a frequency that is an integral multiple (X2, X3, etc.) of a fundamental (X1) frequency. HARMONIC DISTORTION: The maximum harmonic content of a periodic output signal, for any given frequency or amplitude within the specified limits, expressed as a percentage of the rms value of the signal.


An ideal shock pulse for which the acceleration-time curve has the shape of one full cycle of a versine curve beginning at zero.


A wave filter having a single transmission band extending from some critical or cutoff frequency, other than zero, up to an infinite frequency.


The phenomenon exhibited by a system in which the response of the system to changes is dependent upon its past response to change. The maximum difference in output of a device, at any measurand value within its specified range, when the value is approached first with increasing and then with decreasing measurand.