The cumal or cumaile (pronounced as 'cool' apparently) is an old Irish unit of value or measure of wealth which is mentioned in the earliest Irish lawtexts.
The original meaning of Cumal was that of a 'female slave', which tells us something about early Irish society if they based their system of values on the enumeration of female slaves. Presumably female slaves were originally used as a medium of exchange, but it later became a measure of both land area and land value, being derived from the amount, or value, of land that would have been equivalent to the value of a female slave.
The cumal therefore became the measure for the basic legal unit of land in Ireland comprising about 34 English acres or 13.85 hectares, generally considered sufficient to graze three cows and also known as tír-cumaile or 'cumal-land'. Hence the satisfaction of a debt enumerated in a given number of cumals could be achieved either by transferring the necessary amount of land or the equivalent number of cows. So depending on the context in which it is used a 'cumal' can be taken to mean either are given amount of land or around three cows.
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