1. A partially-ejected clump of feces. Half a loaf.
2. An ejected clump of feces that is not heavy enough to drop off your dingleberry forest.
Once a grogan drops off your arse by whatever means, (rocking, banging against the seat, coaxing with paper or your fingers) it becomes a turd. If you let the grogan remain, it becomes a massive dingleberry, once it dries. Grogans are moist; dingleberries are dry. (See dingleberry)