Brain freeze
Etymology
An informal 20th-century American coinage. Its clinical name is grander: "sphenopalatine ganglioneuralgia," referring to a nerve cluster behind the nose. The pain comes not from the brain freezing but from cold rapidly narrowing and then dilating blood vessels in the palate, which nearby nerves misread as head pain.
noun phrase · /BRAYN freez/
A sudden, sharp headache triggered by eating or drinking something very cold.
What it names
A common, harmless pain whose real mechanism is surprisingly well understood — a handle for a shared bodily glitch.
Example
He inhaled the milkshake and paid for it with ten seconds of brain freeze.
Related idea
Brain freeze is referred pain — the injury is in the palate, but the nerve pathway reports it as coming from the forehead, the same trick behind a heart attack felt in the left arm.
See also