is short for 'glatzkopf' - the German word to describe somebody as bald. Used by English-speakers so as to codify someone's baldness with a view to discussing it openly in front of them. See 'beglatzed'.
Jeff: "Have you seen Cody's bald head? What a loser."
Brian: "Oh, hey Cody!"
Cody: "Hi guys."
Brian: "You're right Jeff - a definite glatz."
"Sheila splashed her wetness right across Barry's glatz"
Gay Steve was dying to spaff all over Bald Tony's glatz.