Is a townhouse like a condo?

A little, but they are different.

A townhouse is usually a row house, one of several attached buildings.

They may have completely separate ownership.

A condominium ("condo") is often more like an apartment but essentially it is a residence that is part of a group that has shared management and maintenance. The condo owner is responsible for inside the walls the a Home Owners Association (HOA) is responsible for the outside and the grounds. The condo owner will pay a monthly fee to the HOA for this work.