Nominative (Basic Form)

The nominative case (nominatiivi) serves three main roles in Finnish:

• The Subject: It marks who or what is performing the action. For example, in Koira nukkuu (The dog sleeps), 'koira' is in the nominative. Note that in an ordinary cardinal subject phrase such as kaksi koiraa, the numeral kaksi is the nominative head and the noun koiraa is singular partitive (e.g., kaksi koiraa nukkuu). Also, indefinite plural subjects in existential sentences take the partitive plural, not the nominative plural (e.g., Pihalla on koiria vs. Koirat ovat pihalla).
• The Predicate Noun: It defines what something is after the verb olla (to be). This applies to singular countable subjects, such as Hän on lääkäri (He is a doctor). Predicate case also depends on the predicate’s own meaning: Vesi on kylmää describes a substance, but Vesi on neste assigns it to a countable category. With plural subjects, He ovat opettajia classifies people as teachers, whereas He ovat nämä opettajat identifies them as these particular teachers. Definiteness of the subject alone does not decide the predicate case.
• The Total Object: The nominative acts as the object in two main scenarios. First, for plural total objects (e.g., Minä ostan kirjat), the nominative plural is used when referring to a specific, whole set (note that partial or indefinite amounts require the partitive plural). Second, for singular objects in specific situations where there is no nominative subject, such as 1st and 2nd person imperatives (e.g., Osta auto! or Ostakaa auto!), passive sentences, and necessive constructions (Minun täytyy ostaa auto). For these singular objects only, it is sometimes technically called the 'endingless accusative'. Note that personal pronouns take their special total-object forms (minut, sinut, hänet, meidät, teidät, heidät). Interrogative kuka has the object form kenet, with some permitted nominative variation in passive questions.

Morphology:
The singular nominative is the basic or dictionary form, perusmuoto, with no case ending. The nominative plural is formed by adding the suffix -t (e.g., talo -> talot). Note that this -t is dropped when a possessive suffix is added (e.g., kirjat -> kirjani), which makes the singular and plural identical, relying entirely on context (kirjani = my book / my books). Additionally, attributive adjectives must agree with the noun in number (e.g., iso talo -> isot talot). In many words, the singular features the strong grade of consonant gradation (e.g., katto), while the plural (katot) uses the weak grade. However, some words use inverse gradation, where the nominative singular is the weak grade (e.g., sade) and the stem is strong (sateen). Finally, some words are Pluralia Tantum, meaning they are grammatically nominative plural but refer to singular concepts (e.g., häät, kasvot).

Note that while the nominative is the dictionary form, it is not always the 'stem' used for other cases. For example, vesi (water) has several stems: veden, vetenä, and vettä. Learn a word’s inflectional pattern along with its dictionary form.