fjórum
Fjórum is a grammatical form of the Icelandic numeral four. In Icelandic, numbers decline like adjectives, so fjórum represents the dative plural of the word for four (fjórir, fjórar, fjögur). It is used with nouns in the dative case and with prepositions that govern the dative; the form is generally the same across genders in the plural.
Etymology and related forms: Fjórum comes from Old Norse fjórir and is cognate with other North Germanic
Usage: Fjórum is commonly seen in time expressions and phrases that express duration or interval, especially
Notes: Fjórum is not used as a simple standalone numeral in counting; rather, it functions within a
See also: Icelandic language, cardinal numbers in Icelandic, Icelandic grammar.