Dictionary.com
definitions

marginal cost

noun Economics.
  1. the cost of one additional unit of any item produced or bought in quantity.

Origin of marginal cost

First recorded in 1925–30
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
marginal cost in Culture

marginal cost

The change in total cost of production when an output is varied by one unit.

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.