Define execution time and execution gap?

I thought they were always given at midnight.

Compilation time & execution time are diff to each other.When an instruction given by the user is performed by the processor,it is said that the particular instruction or command is executing.But...

The time between a program starting and finishing. ie, the time it takes to execute the program.

The execution time of a program is the difference between the start time and the ending time - how long it takes to run from startup to completion.