A space habitat or spacestead is a theoretical space station that rotates to simulate gravity and is outfitted like an environment on Earth, with landscaping, a settlement, etc. These would be very big, on the order of 800+ meters in diameter
Proposed designs include but are not limited to
O'Neill cylinders - Tin can shaped spacesteads with habitable space all over the inside with the exception of the ends.
Stanford toruses - Donut shaped habitats in which the land, settlement, water, etc is on the outer part of the interior, leaving the other half to be the sky. These would also have spokes and a central hub in the middle.
Bernal Spheres - Spherical habitats several kilometers in diameter with the whole inner surface being habitable land.
Bishop rings - Essentially smaller Stanford toruses without central spokes.
Birch Worlds - Spherical habitats one or two light-years in diameter built around a galaxy's supermassive black hole
Space habitat can also mean a base or enclosed settlement on or beneath the surface of a planet or large natural satellite or floating in its atmosphere.