ounce (oz)

The apothecary ounce (used in the USP) contains 8 dr & is equivalent to 31.10349 grams; the avoirdupois ounce is equivalent to 28.35 grams. One liter is equivalent to approximately 33.814 fluid ounces.

References

Stedman's Medical Dictionary 26th ed, Williams & Wilkins, Baltimore, 1995