What is three score?

Three score is a term that refers to the number 60. It is commonly used in old-fashioned or formal language to indicate a specific number of years or items. For example, "three score years ago" would mean 60 years ago.

In music, a score traditionally refers to a set of 20 musical lines on which notes are written. So, three score would be 60 musical lines.

In Abraham Lincoln's Gettysburg Address, he famously said, "four score and seven years ago," which meant 87 years ago. This usage of the term has become quite well-known in American history.