fl oz

fl oz fluid ounce.

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fl oz or fl. oz.

abbr.

fluid ounce

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ounce (oz) [owns]

1. in the apothecaries' system, a unit of weight equal to ¹⁄₁₂ of a pound or 480 grains (31.103 grams); symbol ℥. See also Table of Weights and Measures in the Appendix.

2. in the avoirdupois system, a unit of weight equal to ¹⁄₁₆pound (28.3495 grams).

fluid ounce in the apothecaries' system, a unit of liquid measure equal to 8 fluid drams (29.57 ml). See also Table of Weights and Measures in the Appendix.

a unit of capacity (liquid measure) of the apothecaries' system. In the United States, it is 8 fluid drams, one sixteenth of a pint, or the equivalent of 29.57 mL. In Great Britain, it is an imperial ounce and is 8 (imperial) fluid drams but is one twentieth of an (imperial) pint, or 28.41 mL. See also Table of Weights and Measures in the Appendix.