'northbound' definitions:

Definition of 'northbound'

From: WordNet
adjective
Moving toward the north; "the northbound lane"; "we took the north train"; "the northward flow of traffic" [syn: northbound, northward]

Definition of 'northbound'

From: GCIDE
  • northbound \northbound\ adj.
  • 1. Moving toward the north; as, northbound traffic.
  • Syn: northward. [WordNet 1.5]
  • 2. intended to be used by vehicles moving toward the north; -- of roads and parts of roads; as, The northbound lane was blocked by an overturned tractor-trailer. [PJC]