\ba Unicode word boundary
athe literal a (9710 / 1418 / 6116) (case sensitive)
\wa Unicode word character
cdthe literal text cd (case sensitive) ?matches at most one character from the set below:
.the literal . (4610 / 568 / 2E16)
,the literal , (4410 / 548 / 2C16)
\s*a Unicode whitespace character, repeated any number of times
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