British spelling of 'appareled'; past tense and past participle of the verb 'apparel,' meaning clothed or dressed.
From Old French 'apareil.' British English doubles the final L before adding -ed when the stress falls on the final syllable: apparel → apparelled. This preserves the short vowel sound in the first syllable.
The 'L-doubling' rule in British English (apparelled vs. appareled) comes from how vowels were pronounced centuries ago. Spelling rules are really fossils from Middle English pronunciation patterns.
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