'corporeal group', material unit, designates a combination of several physical phenomena constituting a temporary unity. Thus, for instance, the so-called 'dead matter' forms the most primitive group, consisting only of 8 physical phenomena, called the 'pure eightfold unit' or 'octad' (suddhatthakakalāpa), to wit: the 4 elements (the solid, fluid, heat, motion); colour, smell, taste, nutriment (pathavī, āpo, tejo, vāyo; vanna, gandha, rasa, ojā).
In Vis.M., and elsewhere, it is also called ojatthamaka-kalāpa, 'the octad with nutriment as the 8th factor'.
The simplest form of living matter is the '9-fold vitality unit' or 'life-ennead' (jīvita-navaka-kalāpa), formed by adding 'vitality' to the octad.
Seven decades, or units of ten (dasaka-kalāpa), are formed by adding to the 9-fold unit one of the following corporeal phenomena: heart (physical seat of mind), sex, eye, ear, nose, tongue or body. -
See Vis.M. XVIII, 4; Compendium of Buddhist Philosophy (PTS), p. 164, 250; Atthasālini Tr., II, 413f.