Why is ounces abbreviated with oz.?

Answer 1

I checked Dictionary.com and found this explanation. It's originally from an Italian word.

Dictionary.com Unabridged (v 1.1) - Cite This Source - Share This
oz.
ounce; ounces.
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[Origin: abbr. of It onza]
Dictionary.com Unabridged (v 1.1)
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2006.