Focus
Focus explained in an easy to understand way:
Imagine you're trying to find the source of a mysterious noise in your house. Just as you might trace that noise back to a hidden spot, perhaps under the floorboards or within the walls, scientists pinpoint the origin of an earthquake beneath the Earth's surface. This underground starting point, known as the earthquake's focus, is like the hidden source of the noise, where the initial rupture occurs, sending vibrations through the ground just as a sound would ripple through your home.
Practice Version
Focus: The underground point where an earthquake starts is called the focus. In simple terms, the focus is the spot beneath the Earth's surface where earthquake energy is released.