12 letters · 20 points in Scrabble
noun a child of your spouse by a former marriage
originFrom Middle English stepchildren, stepchildre, remodelled based on child from Old English stēopċild (nominative/accusative), stēopċilda (genitive), and stēopċildum (dative) ("stepchildren"). Equivalent to step- + children.
Etymology from Wiktionary, CC BY-SA 3.0