Ounce | Unit Of Weight | Britannica

Ask the Chatbot Games & Quizzes History & Society Science & Tech Biographies Animals & Nature Geography & Travel Arts & Culture ProCon Money Videos ounce Introduction References & Edit History Quick Facts & Related Topics Quizzes Fun Facts of Measurement & Math Contents Technology Engineering Mechanical Engineering ounce unit of weight Ask the Chatbot a Question More Actions Print Cite verifiedCite While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Select Citation Style MLA APA Chicago Manual of Style Copy Citation Share Share Share to social media Facebook X URL https://www.britannica.com/science/ounce Feedback Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback

Our editors will review what you’ve submitted and determine whether to revise the article.

External Websites Ask the Chatbot a Question Also known as: oz Written and fact-checked by Britannica Editors Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree.... Britannica Editors History Table of Contents Table of Contents Ask the Chatbot

ounce, unit of weight in the avoirdupois system, equal to 1/16 pound (437 1/2 grains), and in the troy and apothecaries’ systems, equal to 480 grains, or 1/12 pound. The avoirdupois ounce is equal to 28.35 grams and the troy and apothecaries’ ounce to 31.103 grams. As a unit of volume, the fluid ounce is equal to 1/16of a pint, or 29.57 millilitres, in the U.S. Customary System and to 1/20of a pint, or 28.41 millilitres, in the British Imperial System. As a unit of weight, the ounce derives from the Roman uncia (meaning “twelfth part”), which was 1/12 of a Roman foot or ounce. The standard or physical embodiment of the Roman foot, a copper bar, constituted the Roman pound standard and was divided along its length into 12 equal parts, called unciae. Thus, uncia designated both a unit of weight and one of length and is the source of the modern terms inch and ounce.