Science & TechnologyGreek → English
Achromatic
/ˌækrəˈmætɪk/adjective
Free of colour, especially of a lens that brings different wavelengths to the same focus.
The Greek roots
ἀ-
a-
without
χρῶμα
chrôma
colour
Literally: “without colour”
The story of the word
Newton concluded that the coloured fringes around a refracting telescope's image could not be cured, which discouraged the whole field for half a century. He was wrong. Chester Moore Hall put crown and flint glass together in the 1730s to cancel the dispersion, and John Dollond patented the achromatic doublet in 1758, taking the Greek for colourless as its name. Musicians use achromatic in the opposite sense from chromatic, sticking to the notes of the scale.
- How it travelled
- Ancient Greek → scientific coinage → English
- First recorded
- 18th century
Same family
chromaticmonochromechromosomeachromatopsia
In a sentence
An achromatic doublet costs three times what a single lens does and is worth it.
The scheme is achromatic apart from one line of red type.