Abstract: The invention concerns a nut for removably fixing any component or device to a longitudinal groove (11) of a profiled element (10) by screwed means. The nut in composed of a body (20) having a base surface (21), a front surface (22), two first opposite sides (23) and two second opposite sides (24), and it has centrally a threaded hole (25) extending from the front surface (22) to the base surface (21) along to an axis (X). The nut body (20) is moreover provided with a rounded area (27) joining every first (23) to every second (24) adjoining side at two diagonally opposite corners, and with side roundings (28) at least in an area of the base surface (21) adjacent to, and joining with, both the two second opposite sides (24). The nut is inserted through the outer opening of a profile groove with combined tilt/oscillation and then rotation movements around the axis of the threaded hole for its arrangement in the use and engage position with the hooking teeth in said groove.