I just had a look at the paper “Comfort in Using Hand Tools” and found quite interesting the different definitions authors give for the term “Comfort”:

According to Peter Vink , Comfort is “a convenience experience by the end‐user during or just after working with the product“.

Wikipedia, on the other hand, defines Usability as a term “used to denote the ease with which people can employ a particular tool or other human-made object in order to achieve a particular goal”.

To me, both of them are quite similar for several reasons:

• They have qualitative attributes;
• They are focused on the end-user;
• They look for best experience.

But curiously, the paper mentioned above just outlines “Usability” once…
The only difference I see between these two concepts could be in the “touching” experience: Comfort is a bit more narrow, more related to physical objects. Usability is a wider concept, including not only physical hardware but also digital sofware.

From now on, I think I would include Confort when talking about Usability. The term sounds human, smooth and friendly…