Which Joe gave his name to ‘sloppy joes’? We look at five interesting sandwiches and their lexical origins.
A unit of refractive power, which is equal to the reciprocal of the focal length (in metres) of a given lens.‘vision corrected to within one dioptre of perfect sight’
- ‘The difference between the focusing powers of these two axes, measured in dioptres, is the astigmatism.’
- ‘The presence of 1 dioptre of refractive error reduces Snellen visual acuity to less than 6/12 that is, below the level needed to drive.’
- ‘The focusing power of a lens is measured in dioptres.’
- ‘Refractive error is measured in dioptres, and myopia is designated with a minus sign.’
- ‘For a typical 3-mm-diameter lens, the dioptric power can be controlled between - 100 and + 50 diopters.’
Late 16th century (originally as diopter, denoting an alidade): from French, from Latin dioptra, from Greek, from di- ‘through’ + optos ‘visible’. The term was used in the early 17th century to denote an ancient form of theodolite; the current sense dates from the late 19th century.
We take a look at several popular, though confusing, punctuation marks.
From Afghanistan to Zimbabwe, discover surprising and intriguing language facts from around the globe.
The definitions of ‘buddy’ and ‘bro’ in the OED have recently been revised. We explore their history and increase in popularity.