I've been using these expressions interchangeably without knowing their possible differences. Longman Dictionary of Contemporary English defines "real-life" as an adjective as follows:
Real-life: actually happening in life, not invented in a book:
Examples: 1) a real-life drama 2) real-life problems
However, it does not define "real-world" as an adjective. It simply defines the real world as "the way life really is, not how people would like it to be or imagine it".
Oxford dictionary defines "real-world" as a noun as follows:
Real-world: The existing state of things, as opposed to one that is imaginary, simulated, or theoretical.
Examples: 1) We live in the real world of limited financial resources. 2) the real-world problems that teenagers face
I could not find "real-world applications" or "real-life applications" in my dictionaries. Google suggests about 566,000 and 479,000 results for these expressions, respectively. If these expressions have the same meaning, then which one is better to use? Which one is more formal?