Rūpa is defined functionally as materiality and sensibility, specifically tactile objectivity or what resists the force of moving mass. Rūpa is defined by its amenability to being sensed rather than its being a mind-independent stuff. It is a content for consciousness if we are to characterize it at all.

As matter, rūpa is traditionally analysed in two ways: as four primary elements and as ten (or twenty-four) derived elements. The four primary elements are solidity, heat, cohesion, and movement.

Four primary elements—ways of imposition on consciousness. Types of imposition. Heat and cold,