1 a [count] : the ability to hold or contain people or things —usually singular ▪ The restaurant has a large seating capacity. [=many people can sit in the restaurant; it has many seats] ▪ What is the hard drive's storage capacity? b : the largest amount or number that can be held or contained [count] ▪ The nightclub has a 1,000-person capacity. ▪ a bottle with a capacity of two liters [noncount] ▪ The prison has reached capacity. [=the prison is full] ▪ The auditorium was filled to capacity. [=was completely full]
2 : the ability to do something : a mental, emotional, or physical ability [noncount] ▪ Some species of birds do not have the capacity [=ability] to fly. ▪ Does he have the capacity to handle this job? ▪ The disease causes a deterioration of breathing capacity. [count] ▪ the machine's computational capacities [=capabilities] —usually singular ▪ a character with a great capacity for love [=a character who is able to love people very deeply]
3 [count] : a usually official position or job : role ▪ He was acting in his capacity as judge. ▪ She's worked for the company in various capacities over the years. [=she has had various jobs at the company] ▪ serving in a supervisory capacity
4 [noncount] : the amount of something that can be produced or managed by a factory, company, etc. ▪ a plan to double the factory's capacity ▪ We can't hire more people because we lack the training capacity. ▪ the nation's oil refining capacity ; also : the largest amount that a factory, company, etc., can produce or manage ▪ The factory is currently running at three-quarter capacity. [=the factory is producing three quarters of what it can produce] ▪ The airport is not expected to reach capacity [=the highest number of planes it can deal with] for several years.