From Middle Low German vrouweken, vrouken, a diminutive of vrouwe, vruwe, from Proto-Germanic *frawjǭ (“lady”), cognate with German Frau (“woman”), Dutch vrouwe (“lady”), vrouw (“woman”) (Danish frue, fru and Swedish fru are borrowed from Low German). For the semantic development of the diminutive, compare German Fräulein (“Ms.”).
Historically only used for unmarried daughters of the nobility, later also daughters of civil servants and the higher bourgeoisie (compare with jomfru which was generally used for daughters of the bourgeoisie in the early modern period), commonly adopted for all unmarried women in the 20th century. Rarely used in daily conversations since around 1970. Common English words like mister, miss etc. have become very archaic in ordinary Norwegian speech during the last decades of the 20th century.
- “frøken” in The Bokmål Dictionary.
As for Bokmål above.
- “frøken” in The Nynorsk Dictionary.