source: chacha.com
A single rise or depression in a series of waves is called a crest or a trough, respectively. Crests are the highest points of a wave while troughs are the lowest points.
The distance from crest to crest in a wave is called the wavelength.
A depression or low place between the crests of a wave is called a trough. It is the lowest point in the wave's cycle and represents the opposite of a crest.
The distance from the crest of one wave to the crest of the next wave is called the wavelength. It is typically measured from crest to crest or trough to trough.
The crest.
A meatus is an opening; therefor, it's a depression, not a projection.
projection
projection
projection
projection
is a depression
....opening?
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.
In anatomy, a crest refers to a prominent ridge or projection on a bone surface, often serving as a point for muscle attachment. These crests provide structural support and aid in the movement of the associated muscles. Examples include the iliac crest in the pelvis and the crest of the tibia in the lower leg.
perpendicular plateThe crista galli.
projection. The bumps of bone around your knees and elbows are almost all called condyles.
A crest is a single rise in a wave, while a trough is a single depression.