8 letters · 11 points in Scrabble
noun interchanging the positions of the king and a rook
verb move the king two squares toward a rook and in the same move the rook to the square next past the king
originEtymology tree Proto-Germanic *kas- Proto-Germanic *kastōną Old Norse kastabor. Middle English casten English cast English -ling English castling From cast + -ling.
Etymology from Wiktionary, CC BY-SA 3.0