1. Rhythmic electrical impulses produced by the brain, typically measured by an electroencephalogram (EEG).
Usage: Usually used in plural form; Technical/medical context
2. A sudden clever idea or inspiration.
Usage: Informal; Usually used in plural or singular 'brainwave'

Examples

• The doctor studied the patient's brainwaves on the EEG monitor.
• Different types of brainwaves are associated with sleep, relaxation, and alertness.
• She had a sudden brainwave about how to solve the math problem.
• His brainwaves led to a revolutionary new product design.
• The researchers measured brainwaves to understand how the brain processes language.
• I had one of those rare brainwaves that changed everything about my approach.