A (usually wooden) structure that projects from a coastline to prevent erosion, longshore drift etc.; a breakwater(noun)
Wiktionary.org : Text is available under the Creative Commons Attribution-ShareAlike License
Use "groyne" in a sentence
"A wrong right: the zebra crossing in Dulwich A sign on Frington beach in Essex which should say 'groyne'"
"Unfortunately, this also reduces sand replenishment on the downdrift side, necessitating the construction of another groyne."
"The officer, always thinly clad (both through the state of his wardrobe and his dread of effeminate comfort), settled his bony shoulders against the rough stonework, and his heels upon a groyne, and gave his subordinate a nod, which meant, “Make no fuss, but out with it.”"