Larnet Share definition Flag The small circular object that disinfects urinals in mens bathrooms, often referred to as a urinal cake. Wow! It's been 3 days and the cleaners still haven't put a new larnet in the urinal! Larnet by Foreegly September 13, 2017 0 0 Get merch Get the Larnet mug. Buy Now — $32.95 See more merch