Short Run

A period of time in which at least one factor of production is fixed. All of the production happens here.
 

Long Run

A period of time in which all factors of production are variable, but technology is changed. All of the planning for the future of the business happens here.
 

Fixed Factors

factors of the business that can't be changed e.g. rent

Variable Factors

Factors that can be changed according to the demand of consumers e.g. employees, operators

Law of Diminishing Returns

The increase of variable factors = the increase of returns until a point where when the variable factors are increase but the returns decrease.