/ˈprɪzəm/
prism
BrE /ˈprɪzəm/
NAmE /ˈprɪzəm/
(geometry)
a solid figure with ends that are parallel and of the same size and shape, and with sides whose opposite edges are equal and parallel
a transparent glass or plastic object, often with ends in the shape of a triangle, which separates light that passes through it into the colours of the rainbow