Number & MeasureGreek → English
Prism
/ˈprɪzəm/noun
A solid with two identical parallel faces joined by flat sides, and in optics a glass wedge that splits light.
The Greek roots
πρίσμα
prísma
something sawn
Literally: “a thing sawn off”
Follow a root:πρίσμα1 word
The story of the word
Πρίζειν is to saw, so a prism is what you get by sawing a block straight through: the Greek names the manufacture rather than the geometry, and Euclid defines the solid in those terms. The optical sense follows Newton, who in 1666 used glass prisms to split sunlight and then recombined it, showing that white light was the mixture and the colours the pure components. A prism adds nothing to light; it only sorts what is already there.
- How it travelled
- Ancient Greek → Late Latin → English
- First recorded
- 1610s
The same roots elsewhere
Other languages reached for exactly the same Greek pieces.
In a sentence
A prism sat on the windowsill and threw a band of colour across the wall each morning.