on high, in the highest

Definition:

The terms "on high" and "in the highest" are expressions that usually mean, "in heaven."

Another meaning for the expression "in the highest" could be, "the most honored."
This expression can also be used literally, as in the expression, "in the highest tree" which means "in the tallest tree."
The expression, "on high" can also refer to being high in the sky, such as a bird's nest that is on high. In that context it could be translated as, "high in the sky" or "at the top of a tall tree."
The word "high" also indicates the elevated location or importance of a person or thing.
The expression "from on high" could be translated as "from heaven."