Entry 1 sense Webster, 1913 Fluvial /flo͞ov'-ē-əl/ · Flu·vi·al · IPA /ˈfluːvi.əl/ 01 a. Belonging to rivers; growing or living in streams or ponds; as, a fluvial plant. 1. Belonging to rivers; growing or living in streams or ponds; as, a fluvial plant.