vertiente
slope
vert-
turn, change
+
-iente
adjective/noun suffix
Vertiente means slope and can be thought of as vert-0 (turn, change0) + -iente1 (adjective/noun suffix1), suggesting something that 'turns' or 'changes' direction, like a slope.
noun
- slopeA slope or side of a mountain where water flowsEl agua fluye por la vertiente de la montaña. // The water flows down the slope of the mountain.