diagnosis

American  

[dahy-uhg-noh-sis] / ˌdaɪ əgˈnoʊ sɪs /

noun

• diagnoses
  plural

1. Medicine/Medical.

   1. the process of determining by examination the nature and circumstances of a diseased condition.

   2. the decision reached from such an examination. Dx

2. Biology. scientific determination; a description that classifies a group or taxon precisely.

3. a determining or analysis of the cause or nature of a problem or situation.

4. an answer or solution to a problematic situation.

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diagnosis British  

/ ˌdaɪəɡˈnəʊsɪs /

noun

1. 1. the identification of diseases by the examination of symptoms and signs and by other investigations

   2. an opinion or conclusion so reached

2. 1. thorough analysis of facts or problems in order to gain understanding and aid future planning

   2. an opinion or conclusion reached through such analysis

3. a detailed description of an organism, esp a plant, for the purpose of classification

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diagnosis Scientific  

/ dī′əg-nō′sĭs /

• diagnoses
  plural

1. The identification by a medical provider of a condition, disease, or injury made by evaluating the symptoms and signs presented by a patient.

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Usage

Plural word for diagnosis The plural form of diagnosis is diagnoses, pronounced [ dahy-uhg-noh-seez ]. The plurals of several other singular words that end in -is are also formed in this way, including hypothesis/hypotheses, crisis/crises, and axis/axes. A similar change is made when pluralizing appendix as appendices. Irregular plurals that are formed like diagnoses derive directly from their original pluralization in Latin and Greek.

Commonly Confused

Although diagnosis and prognosis are both very familiar medical terms, they are sometimes used interchangeably (by nonmedical people), as if they were synonymous words. They are not. When a person is unwell and asks a doctor what is wrong with them, what they are asking for is a diagnosis. Examining the symptoms, as with a thermometer or stethoscope, and evaluating the results of a procedure such as a throat culture, blood test, or x-ray will help the doctor identify the patient’s illness. Whatever that ailment may be, the identification, or naming of it, is the diagnosis. The diagnosis of rheumatoid arthritis was very disheartening. The diagnosis is an acute case of tendinitis. Once a patient has been given a diagnosis, the next thing they’ll want to know is what sort of an outcome they can expect, which means they want to know the prognosis. Unlike diagnoses, which are conclusively based on tangible evidence, prognoses are reasonable predictions based on past observations of similar cases. A prognosis gives the patient an idea of what to expect about the course of their illness, including the probability of recovery. As ailments range from the most superficial to the most life-threatening, it is typical for the word prognosis to be qualified by such adjectives as excellent, favorable, good, positive, negative, poor, dire, grim. Doctors will never tire of telling us, “Early detection and treatment are your best bets for a positive prognosis.” And no one wants to say, “The prognosis was so poor that he could no longer hide his condition from his family.” In nonmedical contexts, diagnosis still carries its meaning of naming or identifying something, especially when that involves a situation or problem. When our computer kept crashing, the tech said that nearby UFO activity could be the reason, so we got another tech—and a proper, earthbound diagnosis! Likewise, prognosis is used outside of medical contexts, retaining its meaning of reasonable prediction. As a lover of pesticide-free smoothies, I’m pleased to say that the prognosis for the future of organic farming has never been better.

Other Word Forms

Derived Forms

• prediagnosis
  noun

Inflected Forms

Nouns

• diagnoses
  plural

Etymology

Origin of diagnosis

First recorded in 1675–85; from New Latin, from Greek diágnōsis “a distinguishing, means or power of discernment”; see dia-, -gnosis

Explanation

When a doctor tells you why you're feeling ill, he gives you a diagnosis. He asks questions, checks your symptoms, and then identifies what's making you sick. Diagnosis is a medical term, but you can diagnose lots of things: problems in a relationship, a coming economic crisis, or the reason the car won't start. If you have a sore throat, runny nose and a bad cough, most of the time doctors will diagnose a cold. If the car won't start and the lights and radio are also off, the diagnosis is simple: your battery’s dead. Anytime you determine the cause of a problem, you give a diagnosis.

Example Sentences

See Examples For:

diagnosis diagnoses

In California, for example, doctors are required to make a mandatory medical report to the state Department of Motor Vehicles for those with a dementia diagnosis.

From MarketWatch ● Aug. 17, 2026

Busch, who said he had never taken a regular medication in his life before the diagnosis, now takes seven to 10 a day.

From The Wall Street Journal ● Aug. 15, 2026

Derry spoke to the BBC about his diagnosis in July 2025, the month he and his bandmates returned to their hometown of Cinderford to play at Cindyfest, which he said was "very, very special".

From BBC ● Aug. 14, 2026

Hormone therapy use was also associated with 39% lower odds of receiving a clinical dementia diagnosis.

From Science Daily ● Aug. 14, 2026

How to retrace my steps back to the way things were before Edie’s texts, before my diagnosis, before Gram died.

From "How to Disappear Completely" by Ali Standish

People with dementia and Alzheimer’s diagnoses and their caregivers also must weigh other big milestones such as stopping driving, quitting a job or handing over management of household finances, Tan said.

From MarketWatch ● Aug. 17, 2026

Clinical geneticist Dr. Xiao P. Peng, who helped confirm Hinken’s family’s diagnoses, said the tools still make mistakes and are better at generating possible leads, translating complex medical jargon and compiling research than making diagnoses.

From The Wall Street Journal ● Aug. 15, 2026

“The process of developing diagnoses is not a fast one.”

From Los Angeles Times ● Aug. 8, 2026

"Anecdotally, we're seeing a lot of people that are either threatening to bring claims or actually bringing claims, that don't have formal diagnoses," says Jo Moseley, a legal director at the firm.

From BBC ● Jul. 24, 2026

At the time Theresa had not dared to; and though later she’d learned to talk professionally — to present cases — past differential diagnoses and treatment plans, she managed nothing.

From "Typical American" by Gish Jen

Related Words

• analysis
• conclusion
• examination
• interpretation
• investigation