börnum

In a sentence

• Ég gaf börnum gjafir.

  I gave gifts to the children.

  The word 'börnum' is the dative plural form of 'börn' (children) in Icelandic, used here to indicate the indirect object (to whom the gifts were given).

• Við töluðum um börnum í dag.

  We talked about the children today.

  In this sentence, 'börnum' is in the dative plural case because the preposition 'um' governs a prepositional phrase requiring the dative case.

• Hún hefur alltaf verið góð við börnum.

  She has always been kind to children.

  Here, 'börnum' is also in dative plural form as it is governed by the preposition 'við', which requires the dative case in this context.