An Etymological Dictionary of the German Language/Thräne
Thräne, f., ‘tear’ (in Swab. and Bav. Zähre is the popular term), from the equiv. late MidHG. trêne, f.; properly the plur. of the MidHG. sing. trahen (contracted trân), m.; corresponding to OHG. trahan (trân), m. (OSax. trahni, plur.), ‘tears’; Teut. base, trahnu-. The equiv. MidHG. traher recalls MidHG. zaher (see Zähre), so that Teut. tahru must have had the parallel forms trahru and trahnu. More definite information concerning the early history of MidHG. trahen, traher, cannot be ascertained.