Borrowed from Italian ferraiolo.

ferraiolo (plural ferraiolos or ferraioli)

1. A kind of cape worn by Catholic clergy over the shoulders, extending down to the ankles and tied in the front.

   Synonym: ferraiolone

• ferraiuolo, ferragiolo (obsolete)

• IPA^(key): /fer.raˈjɔ.lo/^[1][2]
• Rhymes: -ɔlo
• Hyphenation: fer‧ra‧iò‧lo

Refers to a type of garment historically imported into Italy from Spain,^[3] and so presumably calqued from Spanish herreruelo (as ferraio +‎ -olo), q.v.

ferraiolo m (plural ferraioli)

1. ferraiolo (kind of cape)

   Synonyms: mantello, tabarro

From ferraio +‎ -olo.

ferraiolo m (plural ferraioli)

1. an iron worker, especially one who makes the iron reinforcement rods

• “ferraiòlo³”, in Grande dizionario della lingua italiana, volume 5 e–fin, UTET, 1968, page 853f.