pääsanoja

Pääsanoja is a Finnish term used in lexicography and information retrieval to refer to headwords or lemmas—the canonical forms of words that entries in dictionaries and indexes are built around. A pääsana serves as the entry unit from which all inflected forms are derived, enabling users to find information by a single base form rather than searching every variant.

In Finnish dictionaries, the choice of pääsana follows conventional patterns. For nouns, the headword is typically the singular nominative form. For verbs, the infinitive form is usually the pääsana. For adjectives, the positive basic form is used as the headword. Other inflected forms, such as plural forms, cases, or different tenses, are listed as related forms derived from the pääsana. This system helps organize vocabulary and supports efficient lookup and comparison.

Examples illustrate the concept. The noun kissa (cat) uses kissoja, kissan, kissojen as inflected forms derived from the pääsana kissa. The verb juosta (to run) has inflections like juoksen, juoksimme, juostua, all derived from the pääsana juosta. The adjective iso (large) yields isompi, suurin, etc., from the pääsana iso.

Beyond dictionaries, pääsanoja are used as indexing terms in corpora, databases, and search systems. They function similarly to keywords, guiding information retrieval and categorization by capturing the essential base forms of words.