English firn

← Old English fyrn (cognate)

← German Firn (borrowed)

← Proto-Germanic *firnijaz (derived)

← Proto-Germanic *fernaz (mention)

← Proto-West Germanic (derived)

← Old High German firni (derived)

← Gothic 𐍆𐌰𐌹𐍂𐌽𐌴𐌹𐍃 (cognate)

← Alemannic German firn (derived)

← Proto-Indo-European *per- (derived)

← Old Norse forn (cognate)

→ English firnification (suffix)