Start-Up Expenses

I have done a lot of research on start-up expenses, including reading the code, but am having a hard time confirming one basic thing:

 

Do start-up expenses include all expenses incurred before the business is operational?

 

I see many examples, but never see the ones I am trying to confirm, like rent, architect expenses, engineer expenses, legal fees associated with zoning, etc. Should I just assume that all of these expenses are start-up expenses because they occurred before I opened my doors?

 

Thanks so much for your help as this has been bothering me for awhile.

 

-Sean