WIP Limit

a self-imposed limit on the amount of work an individual or team may have in progress at any time. WIP limits are what make kanban a pull system. When a card is finished, it signals available capacity and causes another card to be pulled into the “In Progress” column.

— Making Work Visible, Second Edition, Dominica Degrandis

Each column—that is, each step in the process—has a limited capacity (called a work-in-progress limit, or WIP limit)

— A Seat at the Table, in “3 - A Nimble Approach To The Table”, Mark Schwartz