What does () mean in regex?

What does () mean in regex?
Description. Regular expressions (shortened as "regex") are special strings representing a pattern to be matched in a search operation. ... For instance, in a regular expression the metacharacter ^ means "not". So, while "a" means "match lowercase a", "^a" means "do not match lowercase a".

Reference:
Regular expressions quick reference - Computer Hope
May 4, 2019

What does () mean in regex?,frequently asked question,question and answer,answer,