Calling someone preeminent means they're truly outstanding or better than everyone else — not in general, but in a specific field or specialty. Such as a preeminent geologist.
The adjective preeminent was first recorded in the mid 15th century and has its roots in the Latin praeeminentem, which means “to project forward, rise above.” And anything that's been described as preeminent certainly does rise above the rest. Preeminent scholars or universities or craftsmen are the best at what they do and are well known because of it.
