Anatomy

The nose is split into two passages by a cartilaginous partition known as the septum; and the entrances to these passageways are the nostrils. Bony projections called turbinates stick out into each breathing passage, which helps to increase the nasal cavity's interior surface. Each side of the nose has three turbinates--inferior, middle and superior. The floor of the nose is formed by a plate of bone called the hard palate.

Respiration

The nose warms, cleans and humidifies the air we inhale; the interior surface is lined with microscopic hairs that filter out particles from inhalations, while mucus secretions promote cleanliness and moistness. Air travels through the nasal cavity to the nasopharynx, where it connects to the throat.

Smell

Mucus membranes comprise most of the lining of the nose's olfactory region, where the sense of smell is located. A small portion of the lining contains the olfactory nerve cells that function as the sensory organs. Protruding from the nerve cells into the nasal cavity are tiny fibers, or dendrites, coated by a thin moisture layer that dissolves particles air carries from odor-generating substances; these chemically trigger the olfactory nerve cells.

Sinuses

Connected to the nose by tiny openings are four air-filled pockets called the sinuses, which are lined with mucus. Their function is unclear.

Other Definitions

The word "nose" has other definitions, including the protuberance or beak at the front of an object; the front of something that bears a resemblance to the human nose, like the front of an aircraft; the forward projection of a weapon or tool; and a sense of smell.

Source:

Encyclopedia Brittanica Online

MedicineNet.com

American Rhinologic Society

Resource:

ARD Dictionary