ClosedUnitInterval surely describes the interval itself, not a member of that interval. The member would be ClosedUnitIntervalValue or something. This is the th

ClosedUnitInterval surely describes the interval itself, not a member of that interval. The member would be ClosedUnitIntervalValue or something. This is the thing it would be nice to have a short name for. Just as we say an integer is a member of the set called the integers. We say our "X" (the word we are looking for) is a member of the set called the closed unit interval.