15 letters · 21 points in Scrabble
noun a quantity added (e.g. to make up for a deficiency)
noun the act of supplementing
originEtymology tree English supplement Proto-Indo-European *-tis Proto-Indo-European *-Hō Proto-Indo-European *-tiHō Proto-Italic *-tiō Latin -tiō Latin -ātiōlbor. Old French -ationbor. Middle English -acioun English -ation English supplementation From supplement + -ation.
Etymology from Wiktionary, CC BY-SA 3.0