Level

From the Simple English Wikipedia, the free encyclopedia that anyone can change

Level can have different meanings:

• Originally, a level was a tool which allowed someone (usually a construction worker) to see if a surface was flat.
• it then came to mean a flat surface.
• then people used it to say somebody has a certain degree of knowledge or skill.
• in videogames, a level is a place the player must get through without losing to advance to the next one.

A water level (a tool used by contruction workers)

Close up, showing a bulb of air. This bulb indicates if a surface is flat.

How this works. On a flat surface (above), the bulb will be in the middle position. On a surface that is not flat, but bent one way or the other, the bulb of air will not be in the middle (below).