land clam Share definition Flag A mass of phlegm expelled from the esophagus onto a surface such as asphalt or concrete. It is the only non-shelled mollusk known to man. While hacking outside Lincoln Center, Charles fathered a land clam on 65th Street land clam by Suburban Boy May 20, 2004 0 0 Get merch Get the land clam mug. Buy Now — $32.95 See more merch