Kielitoimiston sanakirja. About 100,000 entries. First published in 2004. Several newer versions exist and are available as printed and in digital form. The dictionary was published as a free online version in 2014, at www.kielitoimistonsanakirja.fi. It is updated about once a year.
For notes on the descriptions of words in Finnish dictionaries, see Descriptions of the vocabulary.
Originally Nykysuomen sanakirja was published in six volumes, later in three volumes. In 1973, a dictionary of international words, Nykysuomen sivistyssanakirja: vierasperäiset sanat, was published. It was later republished carrying the additional title Nykysuomen sanakirja 4, as if it were a new volume continuing the three-volume series. Further confusion has been caused by the publication of a book titled Nykysuomen sanakirja 5 in 1980, which is actually four previously published books bound to one volume: Uudissanasto 80 (newer words from the 1960s and 1970s), Slangisanat = Nykyslangin sanakirja (dictionary of slang), Lyhenteet (dictionary of abbreviations), and Ulkomaiden paikannimiä (foreign place names). These publications can still be useful, but normative information in them may be outdated.
Suomen kielen perussanakirja consists largely of an abridged version of Nykysuomen sanakirja, but with rare words omitted, descriptions abridged, and new material added, with a total of about 100,000 entries. Published in 1990–1994. Kielitoimiston sanakirja is basically a modernized version of Suomen kielen perussanakirja.
Suomen kielen sanakirjoja verkossa ja muualla.
Suomen murteiden sanakirja (SMS). Intended to be an extensive dictionary (with 350,000 entries) of dialects of Finnish as spoken in the first half of the 20th century. Only 8 printed volumes, covering a–kurvottaa, were published, in 1985–2008. It was decided in 2010 that publication proceeds online only. As of 2025, the online version of SMS contains entries from the range a–nysäveitsi.
Oikeeta suomee – suomen puhekielen sanakirja contains about 7,000 words and sayings commonly used in spoken Finnish. Published in 2006.
The web site Joukahainen contains information about inflection of nouns, adjectives, and verbs. Though unofficial, it can be useful, since it contains words that are not yet covered in official dictionaries. Address: joukahainen.puimula.org
Finto.fi is “a centralized service for interoperable thesauri, ontologies and classification schemes for different subject areas It contains a large number of terminological collections. Note: Selecting English as the user interface also sets the search language to English, so you need to set it manually to Finnish in order to search for Finnish words.
Suomalainen fraasisanakirja. A phrase dictionary, first edition in 1974, sixth corrected version in 1985. Over 7,000 phrases.
Suurella sydämellä ihan sikana: suomen kielen kuvaileva fraasisanakirja. A phrase dictionary, published in 2008. Relatively small set of phrases, with longish explanations.
Finto, a thesaurus and an ontology service on Finnish and Swedish. The user interface is partly available in English, via finto.fi/en/. Finto contains several different vocabularies and ontologies, with varying level of maturity and reliability.
IATE, the multilingual term base of the EU, with words in the official languages of the EU, including Finnish. Voluminous, of varying quality of terminological data, but with classification according to reliability. Available at iate.europa.eu, with user interface selectable in different languages.
Webxicon.org or its Finnish-language interface sanakirja.org. A multilingual dictionary based on Wiktionary. With a good user interface that works even in very small devices. A large amount of data, but with no guarantee of reliability or quality, and usually very short explanations.
For serious study of Finnish, you need large bilingual dictionaries in both directions, typically with English, Swedish, German, or French as the other language. They are available in printed form (to some extent even via Amazon) and in digital form (e.g. MOT dictionaries from Kielikone via sanakirja.fi).
Suomen kielen sanaa koskevan tiedon haku eri lähteistä. A page with a form for searching from some dictionaries mentioned above as well as links to other resources on Finnish vocabulary.
The most comprehensive grammar of Finnish is Iso suomen kielioppi (ISK). As a printed book, it has about 2,000 pages. Its online version, VISK, is available at scripta.kotus.fi/visk/.