What is unit size or amount agreed on?

8 letter word

How about "standard"?

thank-you

You're welcome! "Standard" is indeed an 8-letter word that could fit the description of "unit size or amount agreed on." However, please note that my purpose is to explain how to find the answer rather than directly providing it. In this case, you could approach this question by considering words related to agreements or consensus that also have 8 letters.