tööni

Tíðni is the Icelandic word for frequency, used across science and everyday language to describe how often something occurs within a given context. In physics and engineering, it refers to the number of complete cycles of a periodic phenomenon per unit time.

Measured in hertz (Hz), frequency f is the reciprocal of the period T (f = 1/T). The angular frequency ω = 2πf is another common expression of the rate of change in oscillatory systems. In many practical contexts, frequency relates to signals, waves, and vibrations, and audible frequencies for humans generally range from about 20 Hz to 20 kHz.

In statistics, tíðni describes how often a value appears in a dataset. Absolute frequency is a simple count, while relative frequency is the count divided by the total number of observations. Frequency distributions organize these counts, and histograms graphically display their shape and spread.

Beyond physics and statistics, tíðni appears in genetics as allele frequency, indicating how common a genetic variant is in a population. In epidemiology and public health, the term can refer to measures of how common a disease or trait is, including incidence and prevalence, within a defined group.

Overall, tíðni conveys the concept of rate or occurrence across disciplines, from the cadence of a waveform to the spread of data or traits within a population.