What is making capacity of a circuit breaker?

Hard to define... A four year old child has the strength to physically "make" a typical household circuit breaker, while a teen would be able to "make" a typical industrial circuit breaker. (The latter breaker being physically much larger than the former.) Circuit breakers have their "breaking capacity" rated in AMPS. A typical household breaker is rated at 20, 30 or 50 Amps. Industrial breakers might be rated at 500 amps or a thousand or even more. Hope this helps but if it didn't answer your question, please rephrase it and ask again.