Molding

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Middle English: apparently from Old French modle, from Latin modulus (see modulus).

wiktionary

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From Middle English moldyng; equivalent to mold +‎ -ing.

etymonline

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molding (n.)

also moulding, early 14c., "act of kneading;" late 14c., "process of shaping any plastic substance into a given form;" see mold (n.1). Architectural sense "construction element modified to introduce varieties of outline or contour" is from mid-15c.; carpentry sense is from 1670s.