/'prɪzəm; `prɪzəm/
n
1 solid geometric shape with ends that are parallel and of the same size and shape, and with sides that are parallelograms 棱柱（体）.
2 transparent object of this shape, usu triangular and made of glass, which breaks up ordinary light into the colours of the rainbow 棱柱体透明物; （通常指）棱镜, 三棱镜. =>illus at spectrum 见 spectrum 插图.

n[C]
[Date: 1500-1600; Language: Late Latin;Origin: prisma, from Greek, 'something cut with a saw'; because of its shape]
a transparent block of glass that breaks up white light into different colours
technical a solid object with matching ends and several sides which are the same width all the way up