Home › Words › W › wellholewellholewellhole · noun — the open space in a floor, to accommodate a staircase.Definition from Wiktionary (CC BY-SA 3.0).EtymologyFrom well + hole.nounThe open space in a floor, to accommodate a staircase.The open space left beyond the ends of the steps of a staircase.e.g.“well-holes of the stairs and chimney” — 1846, W. M. Buchanan, The Dictionary of Science and Technical Terms Used in Philosophy, Literature...:A cavity which receives a counterbalancing weight in certain mechanical contrivances, and is adapted also for other purposes.Definitions & examples from Wiktionary (CC BY-SA 3.0).