Utilization

n. employment, use of; putting to practical use

In queueing theory, utilization is the proportion of the system's resources which is used by the traffic which arrives at it. It should be strictly less than one for the system to function well. It is usually represented by the symbol . If then the queue will continue to grow as time goes on. In the simplest case of an M/M/1 queue (Poisson arrivals and a single Poisson server) then it is given by the mean arrival rate over the mean service rate, that is, where is the mean arrival rate and is the mean service rate.
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Noun
1. the act of using; "he warned against the use of narcotic drugs"; "skilled in the utilization of computers"
(synonym) use, usage, utilisation, employment, exercise
(hypernym) activity
(hyponym) practice
(derivation) use, utilize, utilise, apply, employ
2. the state of having been made use of; "the rate of utilization"
(hypernym) state

(n.)
The act of utilizing, or the state of being utilized.
  

the actual hours a tool is producing product divided by the scheduled production hours for the tool.