To "consume" a character means a matching rule will use the character up making it no longer available to following rules. Normally a matching meta character will consume all characters it matches.
For example, if the matching expression "*reindeer*soul!" was used to match the sentence, "Those evil reindeer, oh how they prance upon my soul!",
First "*" would consume "Those evil"
then the word "reindeer" would be consumed.
the second "*" would consume ", oh how they prance upon my "
and finally "soul!" would be consumed.