treated as singular The branch of optics that deals with reflection.
- ‘The catoptrics contain the following problem, known as Alhazen's problem: from two points of the plane of a circle to draw lines meeting at point of the circumference and making equal angles with the normal at that point.’
- ‘This was a particular account of microscopes and telescopes, from Mr. Huygens, with an introduction showing the discoveries made by catoptrics and dioptrics.’
- ‘These apparently frivolous aesthetics derive from the serious work in catoptrics of an earlier generation of Minim monks shuttling back and forth between the Place Royale in Paris and the Trinità ai Monti in Rome.’
- ‘But we do know that Niceron illustrated a lovely example on Plate 18 of the third book (on catoptrics) of La perspective curieuse, accompanied by a fascinating discussion on pages 78-80 of the text.’
- ‘When catoptrics are combined with conventional lens systems, known as dioptrics, the resulting sensors are known as catadioptrics.’
Mid 16th century (originally catoptric): from Greek katoptrikos ‘reflecting’, from katoptron ‘mirror’.
We take a look at several popular, though confusing, punctuation marks.