type of photograph on glass with lights given by silver and shades by a dark background showing through, 1855, American English, apparently from Greek ambrotos "immortal, imperishable" (see ambrosia), with second element from daguerreotype.
This invention consists in an improved process of taking photographic pictures upon glass, and also of beautifying and preserving the same, which process I have styled "ambrotype." My improved process has reference to the art of taking pictures photographically on a film of collodion upon the surface of a sheet of glass, the collodion being suitably prepared for the purpose. By the use of the said process, the beauty and permanency of such pictures are greatly increased, and I have on this account styled the process "ambrotype," from the Greek word ambrotos, immortal. ["Specification of the Patent granted to James A. Cutting, of Boston, in the United States of America, Photographer, for an Improved Process of taking Photographic Pictures upon Glass and also of Beautifying and Preserving the same. Dated London, July 26, 1854," printed in Journal of the Franklin Institute, September 1855]
Proto-Indo-European root meaning "to rub away, harm." Possibly identical with the root *mer- that means "to die" and forms words referring to death and to beings subject to death.
It forms all or part of: amaranth; ambrosia; amortize; Amritsar; immortal; manticore; marasmus; mare (n.3) "night-goblin, incubus;" morbid; mordacious; mordant; moribund; morsel; mort (n.2) "note sounded on a horn at the death of the quarry;" mortal; mortality; mortar; mortgage; mortify; mortmain; mortuary; murder; murrain; nightmare; post-mortem; remorse.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit mrnati "crushes, bruises," mriyate "to kill," martave "to die," mrta- "died, dead," mrtih "death," martah "mortal man," amrta- "immortal;" Avestan miriia- "to die," miryeite "dies," Old Persian martiya- "man;" Hittite mer- "to disappear, vanish," marnu- "to make disappear;" Armenian meranim "to die;" Greek marainein "to consume, exhaust, put out, quench," marasmus "consumption," emorten "died," brotos "mortal" (hence ambrotos "immortal"); Latin mors (genitive mortis) "death," mori "to die;" Armenian merani- "to die;" Gothic maurþr, Old English morþ "murder;" Old Irish marb, Welsh marw "dead;" Lithuanian mirti "to die," mirtis "death;" Old Church Slavonic mreti "to die," mrutvu "dead;" Russian mertvyj, Serbo-Croatian mrtav "dead."