Old Norse er

← German er (cognate)

← Proto-Germanic *iz (inherited)

← Proto-Germanic *isti (inherited)

← Westrobothnian jär (link)

← Proto-Norse ᛁᛊᛏ (inherited)

← Old High German er (cognate)

← Gothic 𐌹𐍃 (cognate)

← Proto-Indo-European *h₁es- (root)

← Old Norse es (mention)

← Old Norse es (mention)

→ English is (cognate)

→ Norwegian Nynorsk e (inherited)

→ Norwegian Nynorsk då (mention)

→ Old Norse es (mention)

→ Old Norse vas (mention)

→ Old Norse þars (mention)

→ Old Norse hvars (mention)

→ Old Frisian -er (cognate)