The third part of the regular expression, \1, is the backreference and tells ColdFusion to refer back to the first subexpression[…]
Source: wiktionary
Subexpression
Synonyms for "subexpression"
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Sample sentences
2 total sentences available.
Something to note that's shared between all subexpressions (as well as scriptblocks) is that the end of a line does not terminate the subexpression.
Source: wiktionary