Nostril

Nose orifice that enables the entry and exit of air

A nostril (or naris , pl.: nares) is either of the two orifices of the nose. They enable the entry and exit of air and other gasses through the nasal cavities. In birds and mammals, they contain branched bones or cartilages called turbinates, whose function is to warm air on inhalation and remove moisture on exhalation.

From Wikipedia, under CC BY-SA. More on occurri.