au·​toph·​a·​gy ȯ-ˈtä-fə-jē How to pronounce autophagy (audio)
: the biological process that involves the enzymatic breakdown of a cell's cytoplasm or cytoplasmic components (such as damaged or unneeded organelles or proteins) within the lysosomes of the same cell
Most of the time, cells sweep away this debris. They even recycle it for fuel. Through the process of autophagy, or "self-eating," cells create specialized membranes that engulf junk in the cytoplasm and carry it to a region of the cell called the lysosome, where the waste is broken down and burned for energy.Gretchen Reynolds
Certain environmental cues (such as starvation, high temperature, low oxygen, hormonal stimulation) or intracellular stress (damaged organelles, accumulation of mutant proteins, microbial invasion) activate signalling pathways that increase autophagy.Beth Levine
… proliferating [cancer] cells maintain a nutrient supply by hijacking a natural cell-housekeeping process called autophagy, in which cells chop up and dispose of damaged or obsolete cell components such as proteins.Nathan Seppa

Examples of autophagy in a Sentence

Recent Examples on the Web Two modules were especially likely to be disrupted in patients with Alzheimer’s: One included proteins involved in degrading and reprocessing proteins and organelles through processes like autophagy and ubiquitination, while the other was involved in glycolysis, the processing of sugars. Rohan Rajeev, STAT, 28 June 2024 The proteins encoded bring together three important functions of the cell: autophagy, immunity and mitochondrial function. Matthew Farrer, Discover Magazine, 13 Apr. 2024 All of this is done to have her body in a state of autophagy, which is the way our body moves out unnecessary and dysfunctional cellular components. Victoria Uwumarogie, Essence, 3 Oct. 2023 To date, most studies on fasting and autophagy have been performed on animals and suggest that autophagy begins after about 24 hours of fasting. Bryant Stamford, The Courier-Journal, 29 June 2023 Fast Lean Pro is a weight loss supplement that works by accelerating the process of autophagy in the body. Amber Smith, Discover Magazine, 25 May 2023 Augmenting autophagy in older individuals with amyloidosis, Kelly hopes, will allow their aged immune cells to take out the trash properly. Amber Dance, Discover Magazine, 13 Apr. 2023 How long to fast for autophagy to begin is up for debate. Erica Sweeney, Men's Health, 31 Mar. 2023 Beclin2 may perform a different role in autophagy in other conditions. Justin Quiles, The Conversation, 8 Feb. 2023

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'autophagy.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


borrowed from French autophagie, from auto- auto- + -phagie -phagy

Note: As a term in cell biology introduced by the Belgian immunologist Jules Bordet (1870-1961) in "La bactériophagie ou l'autolyse microbienne transmissible," Volume jubilaire publié à l'occasion du centenaire de la Société royale des sciences médicales et naturelles de Bruxelles (Brussels, 1922), p. 363.

First Known Use

1924, in the meaning defined above

Time Traveler
The first known use of autophagy was in 1924

Dictionary Entries Near autophagy

Cite this Entry

“Autophagy.” Dictionary, Merriam-Webster, Accessed 17 Jul. 2024.

Medical Definition


au·​toph·​a·​gy ȯ-ˈtäf-ə-jē How to pronounce autophagy (audio)
plural autophagies
: digestion of cellular constituents by enzymes of the same cell
autophagic adjective
Last Updated: - Updated example sentences
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