The present participle of 'apparel,' meaning to dress or clothe someone; putting on or dressing in clothing.
From Old French 'apareil.' The -ing suffix transforms the verb into its continuous form. English preserved the American spelling 'apparel' → 'appareling' (one L before -ing), while British English often doubles the L.
English spelling rules are weirder than they look: 'appareling' vs 'apparelling' shows the Great Vowel Divide between American and British English. One simple spelling choice reveals which side of the Atlantic you're from.
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