Why is the ninth month called September?
pertaining to the banks of a river or stream
Latin ripa 'bank, shore'
"of or pertaining to river banks," 1849, with -an + Latin riparius "of a river bank," from riparia "shore," later used in reference to the stream flowing between the banks, from ripa "(steep) bank of a river, shore," probably literally "break" (and indicating the drop off from ground level to the stream bed), or else "that which is cut out by the river," from PIE root *rei- "to scratch, tear, cut" (cf. Greek ereipia "ruins," eripne "slope, precipice;" Old Norse rifa "break, to tear apart;" Danish rift "breach," Middle High German rif "riverbank, seashore;" English riven, rift).
Relating to or inhabiting the banks of a natural course of water. Riparian zones are ecologically diverse and contribute to the health of other aquatic ecosystems by filtering out pollutants and preventing erosion. Salmon in the Pacific Northwest feed off riparian insects; trees such as the black walnut, the American sycamore, and the cottonwood thrive in riparian environments.