rille
A long narrow depression between waves is known as a trough. It is the lowest point of a wave where the water level is at its lowest. Troughs are followed by wave crests, the highest points in a wave.
I don't
A long narrow mark could be a scratch on a surface, a streak of light, or a thin line drawn with a writing implement.
A fissure is an opening or crack in the Earth's crust, typically where tectonic plates meet. It is not a projection or depression, but rather a narrow, long fracture in the ground.
a valley
false
# A small brook; a rivulet. # A long narrow straight valley on the moon's surface
The word you are looking for is "trench." Trenches are long and narrow depressions in the seafloor characterized by very steep sides.
The long narrow bone in the lower part of your leg is called the fibula.
A long or flat narrow muscle :)
A rubber band, obviously
Another name for a lunar valley is a rille. These are long, narrow depressions on the moon's surface that can be several kilometers wide and hundreds of kilometers long. Rilles are believed to have formed through a combination of volcanic and tectonic processes.