frontal sinus

noun

Medical Definition of frontal sinus 

: either of two air spaces lined with mucous membrane each of which lies within the frontal bone above one of the orbits

Learn More about frontal sinus

Share frontal sinus

Comments on frontal sinus

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

WORD OF THE DAY

by word of mouth

Get Word of the Day daily email!

Test Your Vocabulary

Name that Food Quiz

Name That Thing

Test your visual vocabulary with our 10-question challenge!

TAKE THE QUIZ
Dictionary Devil

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

TAKE THE QUIZ

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!