Ethics:

Ethics is the set of some moral values and principal that differentiate right and wrong morally.

Revenue:

Revenue means anything the company received in return, cash, cash claim, any asset, etc.

It is recognized when earned and realized not only when received.

Round-trip transaction:

It is a type of transaction between two or more companies to boost revenue and assets of both the companies but does not result in economic benefit to any company. This is not illegal but unethical.