au·​toph·​a·​gy | \ ȯ-ˈtä-fə-jē How to pronounce autophagy (audio) \

Definition of autophagy

: 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

First Known Use of autophagy

1924, in the meaning defined above

History and Etymology for autophagy

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.

Learn More About autophagy

Time Traveler for autophagy

Time Traveler

The first known use of autophagy was in 1924

See more words from the same year

Dictionary Entries Near autophagy




See More Nearby Entries 

Statistics for autophagy

Cite this Entry

“Autophagy.” Dictionary, Merriam-Webster, Accessed 19 Jan. 2022.

Style: MLA
MLACheck Mark Icon ChicagoCheck Mark Icon APACheck Mark Icon Merriam-WebsterCheck Mark Icon

More Definitions for autophagy


au·​toph·​a·​gy | \ ȯ-ˈtäf-ə-jē How to pronounce autophagy (audio) \
plural autophagies

Medical Definition of autophagy

: digestion of cellular constituents by enzymes of the same cell

Other Words from autophagy

autophagic \ -​jik How to pronounce autophagy (audio) \ adjective


Test Your Vocabulary

Difficult Spelling Words Quiz

  • alphabet pasta spelling help
  • Which is the correct spelling?
Spell It

Can you spell these 10 commonly misspelled words?

Universal Daily Crossword

A daily challenge for crossword fanatics.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!