n (uncountable|business|accounting) The expense of a business not directly assigned to goods or services provided.
n (countable|business|accounting) The items or classes of expense not directly assigned to goods or services provided.
n (uncountable) Any cost or expenditure (monetary, time, effort or otherwise) incurred in a project or activity, which does not directly contribute to the progress or outcome of the project or activity.
n (transport) The system of overhead wires used to power electric transport, such as streetcars, trains, or buses.
n (computing) data or steps of computation that is only used to facilitate the computations in the system and is not directly related to the actual program code or data being processed.
n (countable) A sheet of transparent material with an image used with an overhead projector; an overhead transparency.