13 letters · 20 points in Scrabble
noun (chemistry) the process of refinement or purification of a substance by distillation
noun the conversion of alternating current to direct current
noun the act of offering an improvement to replace a mistake; setting right
originFrom Middle English rectificacioun, from Old French rectificacion, from Late Latin rectificatio.
Etymology from Wiktionary, CC BY-SA 3.0