The definitions are found in Chapter 3 of the Standard. If a word in the text is in italics, it can be found in Chapter 3. It is very important to look at the definitions. The information in Chapter 3 can clarify the meaning of the section you are interpreting.
The definitions contain all of the information needed for calculating the day-lighting areas required in the envelope and lighting section. The top-lighted area and side-lighted area calculations are explained with diagrams.
Opinions expressed here are solely my own and do not express the views or opinions of ASHRAE or the 90.1 committee.