'Prism' is Greek for 'something sawn' — it became optical after Newton split white light into colors.
A transparent optical element with flat, polished surfaces that refracts light, typically separating white light into a spectrum of colours. A geometrical solid with two identical parallel polygonal bases. Figuratively: a perspective or viewpoint that separates a complex whole into components.
From Late Latin prisma, from Greek πρίσμα (prísma, "something sawn, a prism"), from πρίζω (prízō) or πρίω (príō, "to saw"). The Greek verb derives from PIE *preh₁i- or *pris- ("to cut, saw"), a root with limited but clear reflexes: Lithuanian pjaustyti ("to cut up") and possibly Old Church Slavonic prĭstŭ ("finger" — the cutting/pointing digit). The original geometric sense referred to any solid whose cross-section is constant
Before Newton's prism experiments in the 1660s, the dominant theory held that prisms created colours by corrupting white light — adding darkness to it in varying degrees. Newton demonstrated the opposite: white light is not pure but composite, and the prism merely separates what is already there. He proved this by passing the separated colours through
Words closest in meaning, ranked by similarity