septum
The openings to the nostrils are call the naries. The singular is a naris.
My wife and I call it a glebe. You may call it whatever you like.
A horse has two nostrils, one on each side of its nose.
They have two nostrils
The openings in your nose are the nostrils.
The platypus's nostrils are on its bill.
Yes, cows do have large nostrils. These large nostrils will allow more air into the lungs than smaller nostrils would.
The nostrils / nares are the openings in the nose.
4 all together... 2 internal nostrils and 2 external nostrils
horses have two nostrils
You could call the 3rd of 4th one the middle
middle school