^start of line
id:the literal text id: (case sensitive) \s*any whitespace character, repeated any number of times
\d+a digit, repeated at least once
\s+any whitespace character, repeated at least once
synset:the literal text synset: (case sensitive) \s*any whitespace character, repeated any number of times
Non-Capturing Group(?:\w+,)* *repeats the group contents below any number of times:
\w+any word character, repeated at least once
,the literal , (4410 / 548 / 2C16)
\w+any word character, repeated at least once
$end of line
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