An Etymological Dictionary of the German Language/Zwilling

by Friedrich Kluge

Zwilling, m., ‘twin,’ from the equiv. MidHG. zwinelinc, zwillinc (g), m. (also zwiselinc and zwilich-kint), and zwinelîn, n., OHG. zwiniling, m. A derivative of the OHG. adj., zwinal, ‘geminus, gemellus,’ and also, like zwinal, from zwi-, ‘twofold’; comp. the equiv. E. twin, Du. tweeling, Dan. tvilling.