Definitions

# Periodicity

[peer-ee-uh-dis-i-tee]
Periodicity is the quality of occurring at regular intervals or periods (in time or space) and can occur in different contexts:

• A clock marks time at periodic intervals.
• A metronome ticks at periodic intervals of time.
• A publication published at periodic intervals can be called a "periodical", for example a magazine.
• In mathematics, a function whose output contains values that repeat periodically is called a periodic function.
• In chemistry, the periodic table is a table which classifies the chemical elements by means of the periodicity of their chemical properties.
• In physics, period is the number of cycles as a result of time (time/cycle). The amount of time it takes to complete one full revolution. Period is also the inverse of frequency.
• In music theory, periodicity is described as "predictability gives rise to expectations".
• Standing waves crest at periodic intervals of distance.
• In finance, the periodicity of a loan describes the interval between payments.
• The measure of periodicity in time is frequency which has the metric units of Hertz.