# Definition:Apothecaries' Weights and Measures/Mass/Ounce

## Definition

The apothecaries' ounce is an apothecaries' unit of mass.

### Conversion Factors

 $\ds$  $\ds 1$ apothecaries' ounce $\ds$ $=$ $\ds 8$ drachms $\ds$ $=$ $\ds 24$ scruples $\ds$ $=$ $\ds 480$ grains $\ds$ $=$ $\ds 1$ troy ounce $\ds$ $=$ $\ds 31 \cdotp 1$ grams

### Symbol

$\mathrm {oz.}$

The symbol for the ounce is $\mathrm {oz.}$

The $\LaTeX$ code for $\mathrm {oz.}$ is \mathrm {oz.} .

## Historical Note

The apothecaries' pound derived from the uncia (Roman ounce).

It is seen that an apothecaries' ounce is the same size as a troy ounce, while weighing approximately $1 \cdotp 1$ ounces avoirdupois.

Some sources do not recognise the existence of the apothecaries' ounce separately from the troy ounce, and when tabulating the various conversion factors refer merely to the fact that $8$ drachms make $1$ troy ounce.

## Linguistic Note on Ounce

The word ounce derives from the Latin uncia, meaning $\dfrac 1 {12}$ part (of an as).

Despite the gradual migration to the metric system, the word ounce still lives on as a rhetorical flourish for something small, for example:

If you only had an ounce of sense you would understand that ...

## Linguistic Note on Apothecary

An apothecary is a medical professional who specialises in formulating and dispensing materia medica to physicians, surgeons and patients.

The modern counterpart is pharmacist (also referred to as a (dispensing) chemist in British English).

However, in some languages and regions the word apothecary can still be found referring to a retail pharmacy or a pharmacist who owns one.

Thus the apothecaries' system of weights and measures focuses largely on small weights and volumes, where the materials being exchanged were renowned for being dispensed in tiny amounts.

The word apothecary derives from the Ancient Greek word ἀποθήκη (apothḗkē), meaning repository or storehouse.

The word migrated via the Latin apotheca, also meaning repository, storehouse or warehouse, to the Medieval Latin apothecarius, meaning storekeeper, and eventually to the Old French apotecaire.