Definition from Wiktionary, the free dictionary
See also: ortho-
ortho (plural orthos)
- (chemistry) An isomer of a benzene derivative having two substituents adjacent on the ring
1887 December 21, Thomas M. Morgan, “On Some Derivatives of Ortho-Nitro-Cinnamic Acid”, Chemical News:
- When the cinnamic acid had been nitrated the ortho was separated from the para, by suspending in alcohol and leading hydrochloric acid gas into the mixture : […] .
- (astronomy) A certain type of flat eyepiece
1998, Terence Dickinson, NightWatch: A Practical Guide to Viewing the Universe, page 76:
- Orthos are excellent eyepieces, still preferred by some backyard astronomers for medium- and high-power applications, especially planetary observing.
- (photography, dated) An orthochromatic plate
1908 June, Charles F. Rice, “On the Use of Orthochromatic Plates”, Photographic Times, page 174:
- Wherever the exposure is likely to be cut short— and this includes all high speed work and most portraiture — the ortho is not so suitable as the ordinary plate.
- (imaging) An orthophoto
2001, Drew Decker, GIS Data Sources, page 105:
- The typical orthophoto building process is a long one, however, and the photography that the orthos are based may be several years old before an orthophoto is ready for distribution.