Legal Definition of Acceleration: Causing a debt to become due immediately, before its scheduled date, due to a default | Learn about the legal definition of acceleration and its importance for business owners. Discover how acceleration clauses can protect your financial interests and help you negotiate better terms. Find out when and how a debt can be accelerated, and the implications it can have for both parties involved. Gain a clear understanding of this legal concept to navigate contractual agreements with confidence and mitigate potential financial challenges