In California there is no legal term "townhouse" it's more the description of the layout. The townhouse is commonly known to be a 2 story home. But normally it's a condo by legal definition.
There are also homes called PUDs (Planned Unit Developments). This is different in that the PUD owners own the land and have a right to use the common areas....in a condo the owner owns the unit and a percentage of the common areas. This is not a huge legal definition....but my brokerage training coming back to mind. :)
Hope this helps....
Scott Bingham, Beach Cities Real Estate
A town house is a term for a style of 2 or three story house that is much like an apartment but with 2 or three levels of living space and are in multifamily buildings. A town house can be a condo but it is the condo association that makes it a condo.
In SoCal, almost all townhomes are condos. Townhomes have no other unit above or below them, but are often attached on the sides, although they don't have to be.
The other part that can be so confusing is that there are also DETACHED Condos (that look like single family homes), and ATTACHED Single Family Homes (that look like townhomes!)
The legal description of the property will tell you exactly what it is!