Tags are there to categorize questions so that we can find them, not necessarily to teach learners concepts they should know. People tag questions to the best of their ability, and if a term isn't widely known to apply to a particular type of question, it doesn't get created. Anyone with 300 reputation or more can create tags just by adding them to a question.
It's great that you found a term that captures an aspect of your question - now we should find more existing questions that need that tag. A tag that has only one question attached to it and no description on what types of questions it is used for isn't very useful.