Learner's definition of CALIBER
level of excellence, skill, etc.
The school will only hire teachers of the highest caliber. [=will only hire the best teachers]
I was impressed by the high caliber of the team's work.
It is exciting to meet a writer of his caliber. [=a writer as good/skillful as he is]
The two colleges are not of the same caliber. [=one of the colleges is better than the other]
a measurement of the width of a bullet or a gun barrel