(psychology) A technique of behavior modification through positive and negative reinforcement and positive and negative punishment.

(mathematics, physics) A differential operator,denoted ∆ and defined on ℝⁿ as 𝛥=∑ᵢ₌₁ⁿ(∂²)/(∂x_i²), used in the modeling of wave propagation, heat flow and many other applications.

A person who operates a telephone switchboard. / A person who provides assistance in establishing a connection, or who provides information or takes messages via the telephone.

(military) That portion of a theater of war] which an army passes over in attaining its object.

A company that sells package holidays.

(finance) Negative operating income.

(UK) Alternative spelling of cooperate

(operations) The application of scientific methods and techniques to problems of decision making, especially in business management and government administration.

(business, accounting) Any expense incurred in running a business, such as sales and administration, as opposed to production.

A subcontractor who may be a commercial carrier, but most often provides capacity (trucks and drivers, with or without trailers or chassis) to either commercial or private carriers under a contract for services.