This page describes an obsolete unit.

The unit described on this page was in use prior to modern methods of precision measurement. It was based on a standard which is no longer available, and which is not capable of being calibrated against modern measurement units. Therefore, the equivalence to modern SI units or to current United States customary units can only be considered approximate.

The amma (ἄμμα, sometimes rendered in translation as cord) was an Attic Greek unit of length or distance. According to Hero of Alexandria, amma is the Greek term for a measure of length, probably Egyptian in origin, which was derived from the string or the rope used to measure out distances.

Value in terms of modern unitsEdit

The Greek units of measuring lengths and distances were well-defined and their relationships to each other are well known, but since no actual Ancient Greek (Attic or other) standards are definitively known by the present day, the only way of determining the length of any Attic Greek unit is to measure something in modern terms whose length was given by the Greeks in their units. And because this procedure does not give us any clue to which unit may have been the base unit and which were subsidiary units, this distinction really does not apply to the Attic Greek units here given, so all the units really have equal status. However, such measurements have been made, and they indicate (though requiring statistical treatment to allow for the inaccuracies of the Greeks' own measurements) that the best estimate of the Attic Greek pous (foot) can be taken as 0.30856 m = 1.0123 ft = 0.3374 yd , and this distance will be adopted on this wiki as the basis for interpreting all other Attic Greek units of length or distance, as their relation to the pous is known. The amma was 60 podoi, and based upon this value of the pous, the length of the amma was 18.5136 m = 20.2467 yd = 0.0115 mi.

Relation to other Attic Greek length unitsEdit

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