Approximate measures

Unregulated volume units still in use

Approximate measures are units of volumetric measurement which are not defined by a government or government-sanctioned organization, or which were previously defined and are now repealed, yet which remain in use. It may be that all English-unit derived capacity measurements are derived from one original approximate measurement: the mouthful, consisting of about 1⁄2 ounce, called the ro in ancient Egypt (their smallest recognized unit of capacity). The mouthful was still a unit of liquid measure during Elizabethan times.

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