Medical Definition of paranasal sinus
: any of various sinuses (as the maxillary sinus and frontal sinus) in the bones of the face and head that are lined with mucous membrane derived from and continuous with the lining of the nasal cavity
Love words? Need even more definitions?Merriam-Webster unabridged
Words at Play
- The Good, The Bad, & The Semantically Imprecise - 5/24/19
- Summer Reading Picks from Merriam-Webster Staffers
- The Wayward Cousins of 'Irregardless'
- Different Words for Luggage and Baggage
Ask the Editors
- On Contractions of Multiple Words
- A Look at Uncommon Onomatopoeia
- Is Singular 'They' a Better Choice?
- Challenging Vocabulary Quiz Returns! Take the quiz
- Time Traveler Quiz: Which Word Came First? Take the quiz
- Spell It Take the quiz
- Dictionary Devil Play the game