1 : a wedge-shaped or tapered piece used to fasten together parts of a structure.

Where did the term cotter pin come from?

"wedge-shaped piece or bolt which fits into a hole used in fastening or tightening," 1640s, of uncertain origin; perhaps a shortened form of cotterel, a dialectal word for "cotter pin or bolt, bracket to hang a pot over a fire" (1560s), itself of uncertain origin. Cotter-pin is attested by 1849.

What is a Chirurgeon?

chirurgeon. / (kaɪˈrɜːdʒən) / noun. an archaic word for surgeon.