Frequency - Dynamic NPU Manual



Number rate of regular event

Definition in words

Number of regular events divided by time elapsed

Alternative expression: Number of periodic phenomenon per time

Note: Regular event is an event that re-occurs after a time

Definition by equation

Systematic terms

Frequency of component B in system 1

Result type

Rational scale
  • Value sets are positive numerical values
  • Algebraic operations are allowed (a=nb; a≠nb)
Numerical values from 0-∞


1/s, 1/min, etc.


  1. Ferard G, Dybkaer R, Fuentes-Arderiu X. Compendium of Terminology and Nomenclature of Properties in Clinical Laboratory Sciences : Recommendations 2016. 1 ed: Royal Society of Chemistry; 2016. 182 p.

Laboratory field



Example 1
Generic abbreviated
NPU21692 Heart—Systole; frequency = ? × 1/min
Full result NPU21692 Heart—Systole; frequency = 88 × one per minute
Abbreviated result NPU21692 Heart—Systole; frequency = 88 × 1/min
Written expression The frequency of Systole of Mr. Smith’s Heart is [88] × 1/min.

Reproduction and Fertility

Example 2
Generic abbreviated
NPU03453 Sem—Spermatozoa rotation; frequency = ? × 1/s
Full result NPU03453 Semen—Spermatozoa rotation; frequency = 10 × one per second
Abbreviated result NPU03453 Sem—Spermatozoa rotation; frequency = 10 × 1/s
Written expression The frequency of Spermatozoa rotation in Mr. Smith’s Semen is [10] × 1/s.


NPU database, and
  • Kind-of-property

    • Nominal kind-of-property

    • Kind-of-quantity

      • Unitary kind-of-quantity

        • Rational unitary kind-of-quantity

          • Frequency


  • Dybkaer R. Concept system on ‘quantity’: formation and terminology. Accredit Qual Assur. 2013;18(3):253-60.
  • Dybkaer R. ISO terminological analysis of the VIM3 concepts ‘quantity’ and ‘kind-of-quantity’. Metrologia. 2010;47(3):127-34.
Date Term Note
1996-01-01 Frequency Term established