Abstract: A chair has a seating surface supported by two, laterally-spaced leg members extending above the seating surface to receive arm rests, a back rest mounted for pivoting at its base on a back end of said seating surface, and the arm rests mounted for pivoting on the back rest. Leg pairs of each leg member converge upwardly and are rigidly joined by a head brace, so as to be stackable. Arm rests, which respectively rest on the head braces, are dismountably secured thereto. A rear end of each arm rest is joined to the back rest via a pivot pin situated above the level of the arm rest when on the head brace, at such a distance from a pivot pin mounting the back rest to the seating surface that the rear end of said arm rest can move beyond the opposite front end of the brace, when the back rest is folded down on, i.e. pivoted to, the seating surface.