Jaksollinen

Jaksollinen is the Finnish adjective meaning periodic, describing phenomena that repeat at regular intervals or follow recurring patterns. The word is formed from the noun jakso (period) with the suffix -llinen, and it is used broadly in scientific and technical language. In ordinary text it is written with lowercase letters unless it appears at the beginning of a sentence or in a title.

In science and mathematics, jaksollinen describes recurring structures or behaviours. In chemistry, the term is closely associated with jaksollinen järjestelmä, the Periodic Table, which groups chemical elements according to properties that recur as their atomic number increases. This periodicity underpins trends in attributes such as atomic radius, electronegativity, and ionization energy. In mathematics, jaksollinen funktio denotes a periodic function, a function for which there exists a fixed period T such that f(x+T) = f(x) for all x. The concept also appears in physics, biology, and earth sciences to describe waves, oscillations, seasonal cycles, and other repeating phenomena.

Overall, jaksollinen functions as a general descriptor for any system or process that exhibits regular repetition, linking terminology across disciplines to a common idea of recurrence. See also: jaksollinen järjestelmä, jaksollinen funktio.