Meaning of "u.b.w."

[lvsiy]

TL;DR Summary

whats the definition of "u.b.w"

Hi im new to chemistry and recently i started to read a chemistry book and saw a shortcut called "u.b.w" it was always after some compound (like. nitric acid/0.9 u.b.w.) tried to looking it up and nothing related showed i think its some kind of mass but like i said im new to chemistry. Sorry for my english but english is not my main language. I would be grateful if someone replies.

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[Nugatory]

Units By Weight?

 

[symbolipoint]

Some abbreviations may never come-up during academic instruction; even some kinds of use of terminology. One may find some abbreviation in use in a certain industry or within some very small few companies. There can be found, OWF for "on the weight of the formula"; for which "formula" is a mixture or blend of materials.