delta
a mature river
A canyon.
a deep, steep-sided, narrow river valley
delta
dick in your mouth
Something that is 8-sided is usually referred to as a octogon.
Blue Sided Leaf Frog's diet consists of mostly arthropods and crickets. But they will eat anything they can get in their mouth.
He is a river god that sided with the Titans against the gods. Zeus then turned him into water for the River Styx.
young
A Rift Valley
A young
Four sided figures are called quadrilaterals. They are usually squares, rectangles, trapizoids, etc..