The minim (abbreviated min or ♏) is a unit of volume in both the imperial and US customary systems of measurement. Specifically it is 1⁄60 of a fluidram[1] or 1⁄480 of a fluid ounce.[2][3]
The minim was introduced in the 1809 edition of the The pharmacopœia of the Royal College of Physicians of London as an alternative to the drop, which had previously been the smallest unit of Apothecaries' measure.[4] It was observed that the size of a drop can vary considerably depending upon the viscosity and specific gravity of the liquid. (At the time, the phenomenon of surface tension was not well-understood.) The minim, on the other hand, was measured with a graduated glass tube known as a "minimometer"[5] later known as the minim-tube,[6]The minim-tube was type of graduated pipette, a device invented in 1791 by Francois Antoine Henri Descroizilles.
Apothecaries' measures are fully described in the Weights and Measures Act of 1878. In the United Kingdom, the 1963 Weights and Measures Act provided for the abolition of the minim, fluid scruple, and fluid drachm, all already obsolete. Actual delegalization occurred on February 1, 1971.
While the use of the minim, along with other such measures, has been reduced by the adoption of the metric system, it still persists in some countries in the measurement of dosages of medicine.
| 1 imperial minim | = | 1⁄480 | imperial fluid ounce |
| = | 1⁄60 | imperial fluidram | |
| = | 59.1938802083 | microlitre (exactly)[7][8] | |
| ≈ | 1⁄500 | US fluid ounce | |
| ≈ | 0.960759940 | US fluid minim |
| 1 US minim | = | 1⁄480 | US fluid ounce |
| = | 1⁄80 | US teaspoon | |
| = | 1⁄60 | US fluidram | |
| = | 61.611519921875 | microliters (exactly)[9] | |
| ≈ | 1⁄461 | imperial fluid ounce | |
| ≈ | 1.040842731 | imperial minims |