Definition of intraclast
Intraclasts are irregularly-shaped grains or clasts that form by syndepositional erosion (i.e. erosion simultaneous with deposition) of partially-lithified sediment. Gravel grade material is generally composed of whole disarticulated or broken skeletal fragments together with sand grade material of whole, disaggregated and broken skeletal debris. The name is mostly applied to fragments of early cemented limestones of local origin. ( adapted from Wikipedia).