perusteisia

Perusteisia is a Finnish adjective form meaning “based on” or “founded on.” It stems from peruste, meaning basis or foundation, and the suffix -inen to form the adjective perusteinen. The form perusteisia is used before a plural noun, typically in contexts where the noun is in a partitive or other inflected form, to describe something as grounded on specific grounds, criteria, or evidence. It is common in formal or academic writing to qualify statements, analyses, or procedures as being based on certain principles. For example, perusteisia vaatimuksia can mean demands based on established criteria, and perusteisia tietoja can mean information based on evidence. The expression is often found in policy documents, research reports, and analytic texts.

Semantically, perusteinen contrasts with perusteellinen, which means thorough or comprehensive; both derive from the same root but serve different grammatical functions. Etymologically, the term belongs to a class of adjectives formed from peruste (basis) plus the -inen suffix. In English translations, perusteinen is typically rendered as “based on” or “grounded in.” The plural form perusteisia is one of several inflected forms used to match number and case in Finnish.

See also: perusteellinen; perusteet; Finnish grammar; basis, foundation.