1550s as an adjective, "pertaining to or being in or toward the north; proceeding from the north," from northern + -ly (2) on pattern of easterly, westerly. As an adverb, "toward the north," from 1590s. Related: Northerliness.
going in a northerly direction
the winds are northerly
North Sea
North Star
north-bound
northeast
north-easter
northerly
northern
northland
Northumbria
northward
northwest