1. Obvious definition: The thick creamy head is the result of the beer being mixed with nitrogen when being poured.
2. The better definition: The thick creamy but exceptionally smooth micro-foam head that sticks to your lips and requires a thorough lip licking and smile to remove.
3. The best head you can get...from a beer.
Man, that girl is like a great beer; she is domestic and imported and gives great Guinness head.