Definition of optogram in English:

optogram

noun

historical
  • An image formed on the retina which, after death, has been rendered permanent by chemical fixatives.

Origin

Late 19th century; earliest use found in Michael Foster (1836–1907), physiologist and politician. From opto- + -gram, after German Optogramm.

Pronunciation

optogram

/ˈɒptəɡram/