diagnosevsdiagnosisWhat's the difference?

Quick tell: diagnose is a verb, diagnosis is a noun, so they fill different roles in a sentence.

Which to use

“diagnose” is a verb and “diagnosis” is a noun - they look or sound alike but fill different roles in a sentence.

#16,889
“diagnose” frequency rank
#5,121
“diagnosis” frequency rank
22010
confusion score

Side-by-Side Comparison

Feature diagnose diagnosis
Definition To determine which disease is causing a sick person's signs and symptoms; to find the diagnosis. The process of, or an instance of, identification of the nature and cause of a medical condition or illness.

Where the spellings diverge

Shared letters are muted; the letters that actually set diagnose and diagnosis apart are highlighted. They share 7 letters in sequence, which is exactly why the eye skips the difference.

8 ch
diagnose
9 ch
diagnosis

Spelling & Dictionary Insight

These two trip readers on the page rather than in the ear: diagnose is /ˈdʌɪ.əɡˌnəʊz/ while diagnosis is /daɪəɡˈnəʊsɪs/. Spoken aloud the problem disappears. In writing it persists, because they differ by 1 letter(s) in length, and the parts of speech differ too (verb vs noun), which is usually the fastest check. Our composite confusion score for this pair is 22010, derived from the frequency rank of both members and their visual similarity.

diagnose is recorded at frequency rank #16,889, classified as averb, pronounced /ˈdʌɪ.əɡˌnəʊz/. diagnosis is at rank #5,121, tagged as anoun, pronounced /daɪəɡˈnəʊsɪs/.

Glosses for this pair are partially populated in our dataset, but the full side-by-side definitions above should still guide you to the right choice.

With a confusion score of 22010, this pair ranks #419,731 of 530,003 scored English confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of diagnose vs diagnosis

Shared letters: adginos. Private to "diagnose": e. Private to "diagnosis": -.

"diagnose" · 8 letters · shape CVVCCVCV  ·  "diagnosis" · 9 letters · shape CVVCCVCVC

Known mistypes of this pair

  • diagnosedaignose · ddiagnose · diaggnose · diagnnose · diagnoes · diagnosse · diagnsoe · diagonse
  • diagnosisdaignosis · ddiagnosis · diaggnosis · diagnnosis · diagnoiss · diagnosiss · diagnossi · diagnossis

Frequency comparison

diagnose#16,889
diagnosis#5,121

Source: FrequencyWords open word-frequency list

Frequently Asked Questions

Can "diagnose" and "diagnosis" be used interchangeably?
No - they are not even the same part of speech. "diagnose" is a verb and "diagnosis" a noun, so a sentence built for one is usually ungrammatical with the other.
Which is more common, "diagnose" or "diagnosis"?
"diagnosis" is the more common of the two: it sits at frequency rank #5,121 in our English list, against #16,889 for "diagnose". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

Remembering diagnose vs diagnosis

The fastest way to pick the right one every time.

  • Check the role first: if you need a verb, it's “diagnose”; for a noun, it's “diagnosis”.
  • See each word in full, definition, IPA, etymology and its other confusables. Full “diagnose” entry
  • Browse more pairs most likely to be confused. Most confusable

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list