The meter, also known as the metric comma or the meter comma, is an unnoticeable 7-limit comma with a ratio of 703125/702464 and a value of approximately 1.6 cents. It is the difference between a stack of three septimal kleismas and a syntonic comma.
Tempering it out leads to the metric temperament, which splits the syntonic comma into three equal parts, one for the septimal kleisma, and two for the septimal semicomma.
See metric microtemperaments for a collection of rank-2 temperaments where it is tempered out.
Metric (31 & 171 & 323)
Comma list: 703125/702464
Mapping: [⟨1 0 2 1], ⟨0 1 1 3], ⟨0 0 -3 -7]]
Badness: 0.1498 × 10-3