foreldrar

Etymology
Once of. It is rare that a word's gender differs between grammatical numbers, but modern dictionaries generally list them as two distinct words — even though their form and declension is similar. The reason for this disparity in usage is the masculine word's lack of singular form.

Noun

 * 1)  parents; mother and father, or any combination thereof (genealogical abbreviation for.)

Usage notes

 * The term is masculine when used in the plural but neuter when used in the singular.