An Etymological Dictionary of the German Language/riechen

by Friedrich Kluge

riechen, vb., ‘to smell,’ from MidHG. riechen, OHG. riohhan, str. vb., ‘to smoke, steam, emit vapour, smell’; comp. Du. ruiken, rieken, ‘to smell,’ AS. reócan, ‘to smoke, emit vapour,’ OIc. rjúka, ‘to smoke, exhale.’ The Teut. root rū̆k signified ‘to smoke’; see further under Rauch and Geruch. In the non-Teut. languages the stem is not found.