[1] The equivalent nomenclature in economics is specific cost.
[2] Direct costs may be either fixed or variable, but typically comprise materials, labour, and specific expenses such as, e.g. a royalty payment to a patent holder for a given production process,[3] all, directly attributable to a cost object.
These include administration, personnel and security costs.
For instance, in civil aviation, substantial costs of a flight (pilots, fuel, wear and tear on the plane, landing and takeoff fees) are a joint cost between carrying passengers and carrying freight, and underlie economies of scope across passenger and freight services.
By contrast, some costs are specific to the services, for instance, meals and flight attendants are specific costs of carrying passengers.