elinvuoden

Elinvuoden is a Finnish term used primarily in population biology, demography and life-table analyses to denote a single year of an organism’s life. It refers to the life-year interval between age x and x+1 for an individual or cohort and is used when summarizing age-specific parameters such as survival, reproduction, or mortality within discrete yearly intervals.

Etymology and form: the word is a compound of elin (life or organism) and vuosi (year). The form elinvuoden is the genitive/definite form of the base unit elinvuosi, and appears in grammatical constructions that require a possessive or specific reference, for example “elinvuoden aikana.” In everyday Finnish-language texts, elinvuosi may be used as the indefinite form, while elinvuoden serves in context requiring a specific life-year.

Usage and context: elinvuoden is commonly encountered in life-table work, cohort studies, and ecological or veterinary research. Researchers may refer to events or parameters occurring during a particular elinvuosi, such as “elinvuoden 3 aikana tapahtuneet kuolemat” (deaths occurring during the third life year) or report age-specific reproduction rates per elinvuosi. The concept helps align analyses with discrete yearly stages of an organism’s life rather than calendar years.

Relationship to related terms: elinvuosi is closely related to other life-history concepts such as elinikä (lifespan or life expectancy) and ikävuosi (age year). While elinikä describes overall lifespan, elinvuosi provides a modular, year-by-year view of an individual's or cohort’s life course. See also life table and demographic analysis.