Early 20th century. Probably from Italian mostaccioli, plural of mostacciolo sweet spiced biscuit from classical Latin mustāceum sweet cake made of must (from mustum + -āceum, neuter of -āceus; compare Italian regional (Piedmont) mostaceu sweet biscuit) + Italian -olo, diminutive suffix; both the biscuits and the pasta tubes typically have a rhomboid shape.