The crossword solution for the term 'HISTORIC LEAD-IN' is PRE, which stands for 'PRECEDING'. This term is used to describe something that happened before or in advance of something else. It is often used to refer to a period of time or event that happened before another event or period of time. For example, a historic lead-in could be used to describe the events leading up to a major battle or the events that took place before a significant political decision.