The span is the basic unit of length used in Anesidore. A span is defined as the distance between middle digit to middle digit of Merrick with his arms perfectly outstretched, which is also exactly the distance from the bottom of his feet to the top of his head.
"Span" may be prefixed either with a multiplier or with a divisor, as in for example: tenspan, hundredspan, tenthspan, hundredthspan.