Abstract: A connection element (1) has a thread (2) that can be made to engage with a mating thread such as, for instance, a nut. The thread includes locking means (3) that acts upon the mating thread. The locking means (3) are formed by flanks (4, 5; 6, 7, 8, 9) of at least one section (10; 11) of the thread (2) whose arrangement with respect to each other is changed vis-à-vis the arrangement of the flanks (18, 19) of the thread (2) outside of the locking section (10; 11) in such a way that, when the thread (2) engages with the mating thread, a locking force is generated on at least one of the flanks (4, 5; 6, 7, 8, 9) of the locking section (10; 11).