Div'ing-bĕll, n.

noun

n. A hollow vessel, sometimes bell-shaped, airtight, except at the bottom, which is open, in which a person may descend into deep water, and remain some time for work or exploration, respiration being sustained by the compressed air at the top, or by fresh air pumped in through a tube from above.

A diving bell suspended underwater from a ship’s crane, with people above and a diver inside the bell.
Diving-bell.