molding n.

also mould, "hollow pattern of a particular form by which something is shaped or made," c. 1200, originally in a figurative sense, "fashion, form; nature, native constitution, character," metathesized from Old French modle "model, plan, copy; way, manner" (12c., Modern French moule), from Latin modulum (nominative modulus) "measure, model," diminutive of modus "manner" (from PIE root *med- "take appropriate measures").

By c. 1300 as "form into which molten metal, etc., is run to obtain a cast." By 1570s as "a form of metal or earthenware (later plastic) to give shape to jellies or other food. Figurative use of break the mold "render impossible the creation of another" is from 1560s.