Old English sidu

← Old English ġesidian (cognate)

← Proto-Germanic *siduz (inherited)

← Old High German situ (cognate)

← Proto-Indo-European *swedʰ- (derived)

← Old Frisian side (cognate)

← Old Saxon sidu (cognate)

→ English custom (cognate)

→ Icelandic siður (cognate)

→ Old Norse siðr (cognate)

→ Saterland Frisian Sidde (cognate)