Sentence:  Typical terms invented to fill this vacuum include sleepies, eye-snot, and bed-boogers. The correct word, however, is <WSD>gound</WSD>. "Collin was never one to dillydally in the morning: by the time he had rubbed the <WSD>gound</WSD> out of his eyes he was usually on his third Manhattan." 
Meaning of the word marked with <WSD> tags:  Mucus produced by the eyes during sleep.