Cucumber Expressions is an alternative to Regular Expressions with a more
intuitive syntax.

Cucumber supports both Cucumber Expressions and Regular Expressions for defining
Step Definitions, but you cannot mix Cucumber Expression syntax with Regular
Expression syntax in the same expression.

On platforms that don't have a literal syntax for regular expressions (such as
Java), Cucumber will create a Cucumber Expression by default. To use Regular
Expressions, add anchors (starting with ^ and ending with $) or forward slashes
(/). For more information, see Cucumber Expression - Java Heuristics.