While Character Classes can be used to sum up the possible variations within a single space, the regular expression language also provides a way to look for multiple multi-character expressions, through the use of parentheses, (), as well as the | symbol.
For instance, if you are looking, in a particular location, for either the word “train” or “bus” you would express that as “(train|bus).”
Alternation can also be used to alternative word spellings as well. If you are looking for either the word “color” or “colour,” one way to build the expression would be “col(o|ou)r.”
Material taken from the book:
all mistakes are my own however…–Joab Jackson