*repeats the group contents below any number of times:
^start of line
Negative Lookahead(?!.*\bLecture\b) .*any character (except for line terminators), repeated any number of times
\ban ASCII word boundary
Lecturethe literal text Lecture (case sensitive) \ban ASCII word boundary
.*any character (except for line terminators), repeated any number of times
\r?optionally matches a carriage return (ASCII 13)
\na line-feed (newline) character (ASCII 10)