Is there a name for X when X bitwise OR Y is Y? I'm wondering if there is a mathematical or computer science term for a number X such that Y | X = Y? For example:
66536 | 1000 == 66536

In this case, 1000 is the &quot;insert name here&quot; of 66536. Perhaps there is no name for this..? I've tried searching for &quot;bitwise OR returns itself&quot; and other such terms but without luck so far.
I would say that $X$ is a subset of $Y$, in terms of bits set.