index case
noun
Simple meaning
The first documented case in a disease epidemic within a population or the first case of interest in an epidemiological investigation: the case of patient zero.
Pronunciation
Say it like this:
indekskaysSay the bold part a little louder.
IPA pronunciation (US)
ˈɪndɛkskeɪs
This word is pronounced essentially the same in American and British English, so one transcription covers both.
IPA (International Phonetic Alphabet) is a standard way of writing speech sounds.
Definition
Everyday modern meanings first, grouped by part of speech.
noun
epidemiology
The first documented case in a disease epidemic within a population or the first case of interest in an epidemiological investigation: the case of patient zero (the index patient).
epidemiology
The earliest documented case of a disease that is included in an epidemiological study
Word Aura™
How this word commonly comes across.
This meaning: (epidemiology) The first documented case in a disease epidemic within a population or the first case of interest in an epidemiological investigation: the case of patient zero (the index patient).
Used this way, index case is a specialist word with a faintly unfavourable edge. This is a clinical use: it belongs to medical description, where it is factual rather than emotive.
- Emotional tone
- Slightly negative
- Formality
- Specialist/technical
- Intensity
- Moderate
- How common
- Specialized
- Connotation
- Critical or judgemental
- Usage feel
- Clinical and detached
Where it naturally appears
- Medicine/healthcare
- Science
- Technical/specialist writing
Usage note
In general conversation this sense usually needs explaining — outside its field, people reach for a plainer word.
Word Aura describes common impressions, not a measurement. Tone changes with sentence, speaker, relationship and situation.
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Dictionary data from Wiktionary via the Free Dictionary API. Simple meanings, combinations and word intelligence are built from verified reference data, no AI is used to load this page.