If something's applicable, it matters in a certain case: it's relevant. If we're going to have rules, shouldn't they be applicable to everyone?
Is the idea that there's only one correct way to pronounce a word applicable when it comes to applicable? There's some disagreement about this among the experts, but you'll hear people pronounce applicable two ways: with emphasis on “app” or with emphasis on “plic.” So take your pick and use this word confidently wherever it's applicable.
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