Northern
Old English northerne (see north, -ern).
wiktionary
From Middle English northerne, from Old English norþerne, from Proto-Germanic *nurþrōnijaz. Cognate with Old High German nordrōni and Old Norse norrœnn.
Morphologically north + -ern.
etymonline
northern (adj.)
"of or pertaining to a region, place, or point nearer the north than some other," Old English norþerna, norðerne "northern, of the north; Northumbrian; Scandinavian," cognate with Old High German nordroni, Old Norse norroenn (see north). With -erne, suffix denoting direction. Related: Northernmost.
Northerner "man from the north of England" is attested from late 13c. as a surname. In the U.S. sense "native or resident of the northern states or territories" it is attested by 1818. Northern lights "aurora borealis" is recorded by that name by 1721 (earlier north-light, 1706).
