A misspelling of 'circumferential,' meaning relating to or forming the outer boundary or circumference of something.
This is a non-standard spelling of circumferential, which comes from Latin circumferre (to carry around), combining circum- and ferre (to carry or bear).
This particular misspelling is fascinating because it adds an extra 'm,' reversing the mental pattern that makes 'circumference' hard to spell—our brains are playing tricks with this word.
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