Quantcast
Merriam-Webster Logo
  • Dictionary
  • Thesaurus
  • Scrabble
  • Spanish Central
  • Learner's Dictionary

blood–brain barrier

play
noun \ˈbləd-ˈbrān-\

Definition of blood–brain barrier

  1. :  a naturally occurring barrier created by the modification of brain capillaries (as by reduction in fenestration and formation of tight cell-to-cell contacts) that prevents many substances from leaving the blood and crossing the capillary walls into the brain tissues



1934

First Known Use of blood–brain barrier

1934


Medical Dictionary

blood–brain barrier

noun

Medical Definition of blood–brain barrier

  1. :  a naturally occurring barrier created by the modification of brain capillaries (as by reduction in fenestration and formation of tight cell-to-cell contacts) that prevents many substances from leaving the blood and crossing the capillary walls into the brain tissues—abbreviation BBB




Seen and Heard

What made you want to look up blood–brain barrier? Please tell us where you read or heard it (including the quote, if possible).

WORD OF THE DAY

the lowest point

Get Word of the Day daily email!

WORD GAMES

Take a 3-minute break and test your skills!

fox-in-summer-forest

Which of these is a synonym of inchoate?

experimental frightening massive formless
Name That Thing

Test your visual vocabulary with our 10-question challenge!

TAKE THE QUIZ
SCRABBLE® Sprint

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ