›to change the way you think about a situation or activity because of new developments or ideas: The whole concept of "retirement" has been redefined in recent years. Public service broadcasting needs to be assessed and redefined in the multi-channel digital world.redefine a business/industry/marketThe bank is in the process of redefining the business of its troubled investment-banking subsidiary.redefine a role/relationship/approachA company that redefines its sales approach without giving its staff the tools to support the new approach can find itself in a worse position than if it had done nothing at all.redefine what/how, etc.Technology has redefined how people make decisions.