1. Below means lower in number or degree than.
Your body temperature is ninety-seven degrees; it is below normal, which is ninety-eight point six.

2. Below can mean lower in rank or level than.
In our company the supervisors are below the directors.
Our offices are on the fourth floor; theirs are below ours, on the third floor. 

3. Below can mean farther along than.
There is a picnic ground just below the bridge.           

4. Expression               

below the belt—unfairly, not according to the rules
He pretended to be her friend, then applied for her job. That was really below the belt.         

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