An Etymological Dictionary of the German Language/Klammer
Klammer, f., ‘cramp, clamp, brace,’ from the equiv. MidHG. klammer, klamer, klamere, f., OHG. *klamara, f., is wanting; Scand. klǫmbr (gen. klambrar), f., ‘vice,’ and MidHG. klamere point to a Goth. *klamra or *klamara, f., which is connected with the Teut. root klam, ‘to press together,’ appearing in Klamm. The equiv. MidHG. klampfer, f., and the ModHG. dial. forms Klamper (Bav.) and Klampfer (Carinthian) are abnormal; comp. also E. clamp and the equiv. Du. klamp, m.; the labial following the m presents some difficulties. Comp. the next word.