A legal term used in contracts to place additional emphasis on the importance of time in the contractual relationship. Eg failure to notify a party within timescales may have damages accelerated because of the value and importance of time agreed at the outset.
It's a contract term that can place big penalties on a supplier or customer by not telling the other contractual partner the 'bad news' in sufficient time. It recognises that delays are expensive in many situations, and the penalties increase for not telling the other party quickly enough.