'Upstream' definitions:

Definition of 'upstream'

From: WordNet
adverb
Toward the source or against the current [syn: upriver, upstream] [ant: downriver, downstream]
adjective
In the direction against a stream's current [ant: downstream]

Definition of 'Upstream'

From: GCIDE
  • Upstream \Up*stream"\, adv. Toward the higher part of a stream; against the current. [1913 Webster]