Definition
A small, lightweight nasal tube that delivers supplemental oxygen to a pilot or passenger by resting just inside the nostrils, used in unpressurized aircraft at moderate cabin altitudes (generally up to 18,000 feet MSL).
Plain English
A thin tube that sits in your nose and feeds you extra oxygen. It is one of the simpler ways to get supplemental oxygen in flight, used at altitudes that aren't extremely high.
Context Anchor
Seen in discussions of aircraft oxygen equipment and pilot oxygen use at altitude.
Derivation
From the Latin cannula, meaning 'small reed' or 'little tube' (a diminutive of canna, 'reed' or 'pipe'). The medical and aviation use kept the literal sense — a small tube that carries something into the body.
Why Pilots Care
Provides a comfortable way to receive required oxygen above 10,000 feet without wearing a full mask for extended periods.
Intuition Check
Do not think of a cannula as only a hospital needle or IV tube. In this aviation context, it usually means the small nose tube used for breathing oxygen.
Example Sentence 1
On their cross-country at 12,500 feet, the pilot used a nasal cannula to maintain adequate oxygen saturation.
Example Sentence 2
During the long cross-country flight, she switched from the mask to the cannula for better comfort at altitude.