Condo is more of an ownership concept. Townhouse is more of a st

Condo is more of an ownership concept. Townhouse is more of a structural concept.
You may picture an apartment building in mind, when talking about condo. Townhouse: naturally a row of units, while each vertically goes bottom up. Not exactly...
If I build a row of "townhouse"-looking units, then there are 2 possible ownerships: 1) fee-simple, sub-divided, home-owner association; 2) condominium association. There are differences, for example: condo association collectively owns the whole land; HOA member actually owns the foot-print land underneath. There are similarities, for example how to share wall in between units, share roof, road maintenance and garbage collections, etc. All the rules and rights could be specified.