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.

---

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

---

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.

---

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

The 77-year-old singer has to take “a series of tests” before being able to tour again, he told the Hollywood Reporter in a health update following his 2025 brain disorder diagnosis.

From Los Angeles Times ● Oct. 16, 2026

And in a setting where a mistranslated word can mean the difference between an accurate diagnosis and a dangerous mistake, the consequences can be severe—or even deadly.

From Slate ● Oct. 16, 2026

Even taking your diagnosis into account, I wouldn’t count out a long life just yet.

From MarketWatch ● Oct. 16, 2026

She said endometriosis, which affects her bladder and bowel, left her in severe pain during shifts and frequently off sick before she received a diagnosis.

From BBC ● Oct. 15, 2026

The market was finally accepting the diagnosis of its own disorder.

From "The Big Short" by Michael Lewis

Mr. Jay reports both sides of the controversy: Essentially, the military suspects a real attack, while the medical establishment generally diagnoses psychogenic illness, one with no physical cause.

From The Wall Street Journal ● Oct. 16, 2026

The study wasn’t focused on healthcare specifically, but it raises important questions about whether patients and doctors using different languages can reliably receive consistent information about diagnoses, treatment options, and medical risks.

From Slate ● Oct. 16, 2026

There are two main types of lung cancer: "small cell" cancers, which spread aggressively and make up about 10 to 15% of diagnoses, and "non-small cell" cancers, which make up the vast majority.

From Barron's ● Oct. 14, 2026

His and Pierina's diagnoses are frequently voiced by fellow protesters, ordinary Spaniards and even the Spanish government.

From BBC ● Oct. 8, 2026

He’s safe inside statistics and diagnoses and actionable next steps.

From "The Science of Breakable Things" by Tae Keller

Random Word

Spin the wheel and learn a new word!

---

Related Words

• analysis
• conclusion
• examination
• interpretation
• investigation

---