See more synonyms for amorphous on
  1. lacking definite form; having no specific shape; formless: the amorphous clouds.
  2. of no particular kind or character; indeterminate; having no pattern or structure; unorganized: an amorphous style; an amorphous personality.
  3. Petrography, Mineralogy. occurring in a mass, as without stratification or crystalline structure.
  4. Chemistry. not crystalline.
  5. Biology. having structural components that are not clearly differentiated, as the nuclear material in certain bacteria.

Origin of amorphous

First recorded in 1725–35, amorphous is from the Greek word ámorphos shapeless. See a-6, -morph, -ous
Related formsa·mor·phous·ly, adverba·mor·phous·ness, noun

Synonyms for amorphous

See more synonyms for on Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

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British Dictionary definitions for amorphous


  1. lacking a definite shape; formless
  2. of no recognizable character or type
  3. (of chemicals, rocks, etc) not having a crystalline structure
Derived Formsamorphism, nounamorphously, adverbamorphousness, noun

Word Origin for amorphous

C18: from New Latin, from Greek amorphos shapeless, from a- 1 + morphē shape
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for amorphous

"shapeless," 1731, from Modern Latin amorphus, from Greek amorphos "without form, shapeless, deformed," from a- "without" (see a- (3)) + morphe "form" (see Morpheus). Related: Amorphously; amorphousness.

Online Etymology Dictionary, © 2010 Douglas Harper

amorphous in Medicine


  1. Lacking definite form; shapeless.
  2. Lacking organization; formless.
  3. Lacking distinct crystalline structure.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

amorphous in Science


  1. Not made of crystals. Glass, amber, and plastics are amorphous substances.
  2. Lacking definite form or shape.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.