Kalipa

Kalapa or rupa-kalapa is a term in Theravada Buddhist phenomenology for the smallest units of physical matter, said to be about 1/46,656th the size of a particle of dust from a wheel of chariot. Kalapas are not mentioned in the earliest Buddhists texts, such as the Tripitaka, but only in the Abhidhammattha-sangaha, an Abhidhamma commentary dated to the 11th or 12th century, and as such not part of common Theravada doctrine.

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