1825, "a residence in a town," from town + house (n.) from a time when well-off families had country houses as well. As a type of suburban attached housing, c. 1968, American English.

A dwelling unit, generally having two or more floors and attached to other similar units via party walls. Can be Strata or Cross lease titled.

A townhouse is a private residence where at least one wall is shared with another residence. 

Refers to a style of upper class house (generally in London) often with 3 or more floors.

Usually a two- or three-story dwelling with shared walls, or a living unit operating under the condominium or townhouse form of ownership.

Definition An attached home that is not considered to be a condominium.

Detached or attached housing forming part of a cluster of homes sharing some common grounds. Normally has own private entrance and private areas. Can be single or multi storey.

Usually a two-storey dwelling registered under a strata title.

Typically, a series of homes which share a common wall but stand on individual lots. The owner holds the title to the land and the home.

A townhouse is an attached dwelling that is not a condominium, however condominiums are also described as townhouses. A townhouse doesn't necessarily share ownership of common areas in the same w [..]

Attached contemporary housing generally having two or more floors plus a garage and attached to other similar units via party walls in the terraced style.Source