When one caughs up chest phlegm and deposits it on the ground, by way of spitting.
"Mind your step, there's a pavement oyster!"
by Suzanne and Tom Hodgkinson January 07, 2006
Human gonads for culinary use.
When the chimp escaped, Dad's pavement oysters were served to the zoo.
by LepraconMcPot April 12, 2009