\ban ASCII word boundary
\p{N}+a decimal digit, letterlike number, or other numeric character, repeated at least once
\s+any whitespace character, repeated at least once
Non-Capturing Group(?:an|year) anthe literal text an (case sensitive) yearthe literal text year (case sensitive) s?optionally matches the literal s (11510 / 1638 / 7316) (case sensitive)
g modifier: global. Finds all matches instead of stopping after the first
m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string