naris

A naris (plural: nares) is an opening of the nasal cavity — essentially a nostril. It serves as the entry point for odorants into the olfactory system and for air during nasal breathing, and also participates in filtering, warming, and humidifying inspired air.

External nares are the nostrils visible on the face, through which air and odorants enter from the environment. Internal nares (choanae) are the posterior openings connecting the nasal cavity to the nasopharynx, allowing air to pass toward the lungs.

Humans have two external nares (nostrils) separated by the nasal septum. Each naris leads into its own nasal cavity, which converges at the choanae to enter the nasopharynx.