 Form. The first collection of aggregates, form or  materiality (rūpa-skandha), stands for objects regarded as compounded entities (saṃskṛta). Form is  understood to be ‘compounded’ in only one of the two  senses in which compoundedness can be interpreted: that of being the  product of causes and conditions (the other refers to entities that  are produced by putting parts together). The category of form also  includes the sensory systems, which from an anatomical and  physiological point of view are material forms.