Xerography or electrophotography is a dry photocopying technique. Its fundamental principle was invented by Hungarian physicist PÃ¡l SelÃ©nyi and based on SelÃ©nyi's publications Chester Carlson applied for and was awarded U.S. Patent 2,297,691 on October 6, 1942. The technique was originally called electrophotography.
A retrospective, generally, is a look back at events that took place, or works that were produced, in the past. As a noun, retrospective has specific meanings in medicine, software development, popular culture and the arts. It is applied as an adjective, synonymous with the term retroactive, to laws, standards, and awards.
Medical Definition of RETROGRADE. 1. : characterized by retrogression. 2. 3. : occurring or performed in a direction opposite to the normal or forward direction of conduction or flow: as.â retÂ·roÂ·gradeÂ·ly adverb. (1) : moving, occurring, or performed in a backward direction (2) : occurring or performed in a direction opposite to the normal or forward direction of conduction or flow â compare anterograde 1 c: contrary to the normal order: inverse. 2. : tending toward or resulting in a worse or previous state.