mainstem

mainstem

English

Etymology

main +‎ stem

Noun

mainstem (plural mainstems)

1. The principal watercourse of a river that has multiple streams
   • 2015 July 9, “Diverse Early Life-History Strategies in Migratory Amazonian Catfish: Implications for Conservation and Management”, in PLOS ONE‎, DOI:10.1371/journal.pone.0129697:

     Piramutaba (Brachyplatystoma vaillantii) make up a second large export fishery and are found almost exclusively in the Amazon River mainstem, whitewater tributaries, and the estuary [30 –32 ].