brain

To struggle to think or remember something.

To be difficult to comprehend.

One's own idea or conception.

The moment of a sudden unexpected discovery.

A protective helmet, as worn, for example, by a motorcyclist, bicyclist, or soldier in combat.

A narrative, commentary, etc. which amuses and holds one's attention, but which lacks intellectual depth or importance.

The migration of educated or talented people from less economically advanced areas to more economically advanced areas, especially to large cities or more developed nations.

Someone who does brain surgery.

Surgery on the brain or, loosely, any part of the nervous system.

A very basic or minimal level of intelligence.

A state in which a new mother is forgetful, absent-minded, or easily distracted.

Obsessively in mind.

To seek information from someone knowledgeable; to ask questions of someone.