The term sitz bath, describing both the process of taking a bath while in the sitting position, with the legs and feet outside, as well as the tub in which this uncomfortable process may be accomplished, is taken directly from the German word for the same.
The curious feature of the term is that it is half the original, half the English translation.
The German is Sitzbad, literally “a sitting bath,” but the first element has been left in German, possibly to introduce an aura of mystery to the process and render attractive, psychologically, a process that most certainly has nothing to commend it from the standpoint of comfort.