Pramana (Sanskrit) [from
pra-
ma to measure out correctly from the verbal root
ma to measure] Measure, a standard, hence authority; thus Vedah pramanah means "the Vedas are the standards."
In Vedanta philosophy, pramana signifies a means of acquiring certain knowledge (prama), six branches being enumerated: pratyaksha (perception by the senses); anumana ( deduction or inference); upamana (analogy or comparison); sabda or aptavachana (trustworthy testimony or revelation); anupalabdhi or
abhava-pratyaksha (proof by the negative method); and arthapatti (deduction or inference from circumstances). To these some schools add: sambhava (equivalence); aitihya (tradition); and cheshta (gesture).