plural index patients
Definition of index patient
: an individual affected with the first known case of an infectious disease or genetically transmitted condition or mutation in a population, region, or family : index case sense 2
Keep scrolling for more
Keep scrolling for more
Test Your Vocabulary
Words of Snow and Ice Quiz
- Which of the following refers to thin, bending ice, or to the act of running over such ice?

Test your knowledge - and maybe learn something along the way.
TAKE THE QUIZ
Anagram puzzles meet word search.
TAKE THE QUIZLove words? Need even more definitions?
Merriam-Webster unabridgedWords at Play
Ask the Editors
Word Games
Words of Snow and Ice Quiz
A selection of words from the chillier parts of t...
Take the quizName that Thing: Toys and Games Edition
It's all fun and games until someone beats your h...
Take the quizTrue or False?
Test your knowledge - and maybe learn something a...
Take the quizSCRABBLE® Sprint
SCRABBLE® fans, sharpen your skills!
Play the game
Share index patient
Time Traveler for index patient
The first known use of index patient was in 1951
See more words from the same year