Definition of upstream
1 : in the direction opposite to the flow of a stream
2 : in or to a position within the production stream closer to manufacturing processes <make most of its money upstream, selling cheap crude … to refineries — John Quirt>
First Known Use of upstream
UPSTREAM Defined for English Language Learners
Definition of upstream for English Language Learners
: in the direction opposite to the flow in a stream, river, etc. : toward the source of a stream, river, etc.
UPSTREAM Defined for Kids
Definition of upstream for Students
: at or toward the beginning of a stream <She rowed upstream.>
Medical Definition of upstream
1: in a direction along a molecule of DNA or RNA opposite to that in which transcription and translation take place and toward the end having a phosphate group attached to the position labeled 5′ in the terminal nucleotide <… stretches of DNA upstream of genes—are known as promoters.—Matt Ridley, Time, 2 June 2003>—compare downstream 1
2: toward the beginning of series of cellular processes : preceding a linked molecular event occurring in a sequence <It's equally important to focus on additional mechanisms that are upstream of amyloid formation and mechanisms downstream that are involved in the actual degenerative processes within neurons.—Marc Tessier-Lavigne, quoted in Science, 17 Sept. 2010>
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