cardinality

Short definition from Wiktionary

Noun

1. 1
   The number of elements a given set contains.
2. 2
   The number of terms that can inhabit a type; the possible values of a type.
3. 3
   The property of a relationship between a database table and another one, specifying whether it is one-to-one, one-to-many, many-to-one, or many-to-many.
4. 4
   The status of being cardinalitial