What is the difference between a condo and an apartment? The building can look identical: the difference is ownership, and it changes who you deal with.
A condominium is a form of ownership, and an apartment is a form of occupancy, which is why the same building can be either. In a condo each unit is owned separately and the owners jointly own the hallways, the roof and the grounds through an association. An apartment building has one owner who rents the units out.
For a renter the practical difference is the landlord. Renting a condo means renting from an individual owner, under the association's rules as well as the lease, and repairs come from a person rather than from an on-site office. Renting an apartment means a company, a leasing office and usually a faster maintenance answer, with less flexibility in the terms.
For a buyer the difference is what you are buying: a condo means monthly dues, an association with rules and a reserve fund, and a resale package to read before closing. What the dues buy and what the association can do are worth more attention than the finishes.
A townhouse is a third thing and it is a building style, not an ownership form: attached, usually multi-storey, and commonly owned as a condominium or fee simple with an association attached.
A worked example
Two identical buildings across a street. In one, each unit has its own owner and a $280 monthly association due covers the roof, the pool and the insurance on the shared parts. In the other, one company owns all ninety units and rents them from an office by the gate.
Questions people ask
Is it cheaper to rent a condo or an apartment?
Neither is reliably cheaper. A condo rental is priced by one owner and can be a bargain or not; an apartment is priced by a company against its own occupancy and often comes with concessions. Compare the total, including what each includes.
Can you buy an apartment?
You buy the unit, and when units are individually owned the building is legally a condominium, whatever the sign says. If the whole building has one owner, the only thing for sale is the building.