The phrase diurnal motion refers to the?

The phrase "diurnal motion" refers to the apparent daily movement of the Sun, Moon, stars, and other celestial objects across the sky. This motion is caused by the Earth's rotation on its axis.

Here's a breakdown:

* Diurnal means "daily" or "occurring every day."

* Motion refers to movement.

Therefore, diurnal motion describes the daily movement of celestial objects as observed from Earth due to our planet's rotation.