tra·pe·zi·us 
(trə-pēzē-əs)
(trə-pēzē-əs)n. pl. tra·pe·zi·us·es
Either of two large flat triangular muscles running from the base of the occiput to the middle of the back that support and make it possible to raise the head and shoulders.
[New Latin, from Late Latin trapezium, trapezium (from the shape of the muscles paired); see TRAPEZIUM.]