a) A building designed to diagnose and treat the sick, injured or dying. Usually has a staff of doctors and nurses to aid in the treatment of patients.
they spide a goodly castle, plast / Foreby a riuer in a pleasaunt dale, / Which choosing for that euenings hospitale, / They thither marcht [...].
b) A building founded for the long term care of its residents, such as an almshouse. The residents may have no physical ailments, but simply need financial support.
See Also: hospitable, hospitality
Wikipedia foundation.