To save this word, you'll need to log in.
\ ˈā-ˈchär- 
\
\Medical Definition of Hr factor
: a substance present in Rh-negative blood and apparently reciprocally related to the Rh factor
Comments on Hr factor
What made you want to look up Hr factor? Please tell us where you read or heard it (including the quote, if possible).
Test Your Vocabulary
Original Meanings Quiz
- Which of the following is the earliest known sense of the word awe?
Can you spell these 10 commonly misspelled words?
TAKE THE QUIZ
Test Your Knowledge - and learn some interesting things along the way.
TAKE THE QUIZLove words? Need even more definitions?
Merriam-Webster unabridgedWords at Play
Ask the Editors
Share Hr factor