The frenulum.
The point directly overhead in the sky dome is called the zenith. It is the highest point in the celestial sphere, opposite to the nadir which is the point directly below one's feet. The zenith is an important reference point for astronomers and navigators.
When the Sun is directly overhead (at zenith) the point below it is called nadir.
A subsatellite point is the point on the Earth's surface directly below a satellite in orbit. This point moves as the satellite orbits the Earth. The subsatellite point is also called the nadir point.
If the dew point temperature is below zero, the air would need to be cooled to that temperature or below for dew to form. At that point, the water vapor in the air would condense directly into ice crystals, in a process called deposition.
its called the Zenith
The point below the epicenter is called the focus. It is where the earthquake originates and radiates outwards in all directions.
The point directly below the epicenter of an earthquake is known as the hypocenter or focus. This is where the seismic waves originate and the point within the Earth where the energy is released from the seismic event.
From the point on the base which is directly below the apex.
It's called my "ankles".
the point directly above the focus is called the epicenter
The lowest point below the rest position of a wave is called the trough. The highest point above the rest position is called the crest.
The point directly above the focus of an earthquake is called the epicenter. It is usually the point of greatest destruction.