nominative is the primary form of nominals in dictionaries, and it is also the
most common case of most nominal words. The functions of the nominative
are seen most clearly when it is compared with the partitive, the second basic
case in the system. The partitive often expresses an indefinite, non-limited
quantity of something, allowing the possibility that there may exist more of
it. The nominative, on the other hand, expresses either a concrete or abstract
whole or a definite, limited, total quantity.
64 Finnish: An Essential Grammar