What exactly consists of 'Business Logic' in an application?

Question

I have heard umpteen times that we \'should not mix business logic with other code\' or statements like that. I think every single code I write (processing steps I mean) con

Answer 1

To simplify things to a single line...
Business Logic would be code that doesn't depend on/won't change with a specific UI/implementation detail.. It is a code-representation of the rules, processes, etc. that are defined by/reflect the business being modelled.