continuum

noun

1. A continuous series or whole, no part of which is noticeably different from its adjacent parts, although the ends or extremes of it are very different from each other.
2. A continuous extent.
3. The set of real numbers; more generally, any compact connected metric space.
4. A touch-sensitive strip, similar to an electronic standard musical keyboard, except that the note steps are 1/100 of a semitone, and so are not separately marked.