Merriam-Webster Logo
  • Dictionary
  • Thesaurus
  • Scrabble
  • Spanish Central
  • Learner's Dictionary


noun, eti·ol·o·gy \ˌē-tē-ˈä-lə-jē\

Definition of etiology

plural etiologies

  1. 1 :  cause, origin; specifically :  the cause of a disease or abnormal condition

  2. 2 :  a branch of knowledge concerned with causes; specifically :  a branch of medical science concerned with the causes and origins of diseases

Examples of etiology in a sentence

  1. The scarf had been purchased in one of those tiny, exquisitely organized stores that can seduce you into thinking it matters less what you wear than how you accessorize what you wear, and the scarf came in just the noncolor colors that I like: mustard and khaki and taupe, shades of dun, nothing too vivid, yet subtly enlivening. I have traced the etiology of this object the better to convey the irrational significance of its loss. —Daphne Merkin, New York Times Magazine, 5 May 1991

  2. I have Freud in my novel as a doctor someone has heard about somewhere, perhaps in Vindobo-na in Pannonia (Vienna in Austria to you), who thinks, though not in so many words, that neuroses have no somatic etiology. I call him Sameach, which is Hebrew for Freud. I also call him Efcharistimenos, which is Greek for Freud. Damn it, I couldn't spell it out more if I tried. —Anthony Burgess, Times Literary Supplement, 2 Aug. 1985

  3. In social terms, regardless of its etiology, memory loss may be a way of coping with harsh reality. —Elizabeth W. Markson, Growing Old in America, (1985) 1987

Origin of etiology

Medieval Latin aetiologia statement of causes, from Greek aitiologia, from aitia cause

First Known Use: circa 1555

Medical Dictionary


noun eti·ol·o·gy

Medical Definition of etiology

plural etiologies

  1. 1:  the cause or causes of a disease or abnormal condition <some types of cancer have a viral etiology> <a multiple etiology in which biological, psychological, and sociocultural factors all play a role—M. E. Jackson et al>

  2. 2:  a branch of medical science dealing with the causes and origin of diseases

Variants of etiology

or chiefly British aetiology \ˌēt-ē-ˈäl-ə-jē\play

Seen and Heard

What made you want to look up etiology? Please tell us where you read or heard it (including the quote, if possible).


to dishevel or rumple

Get Word of the Day daily email!


Take a 3-minute break and test your skills!


Which of these is a synonym of nonplus?

disapprove reduce soothe perplex
Name That Thing

Test your visual vocabulary with our 10-question challenge!


Test Your Knowledge - and learn some interesting things along the way.