Ethics is defined as moral decision-making. Since each person decides what is morally right and wrong for his or her self, morality is a complex concept. Business ethics are even more complicated, because businesses are built on legal and ethical principles that can vary based on management and the individuals involved.
In any field, the term "ethics" refers to a set of guidelines that differentiate between actions that are right and those that are wrong. The term can also refer to the study of those guidelines -- trying to decide what the guidelines are and how they can best be followed.
In business, the study of ethics tries to determine which actions are and are not acceptable in the field of commerce. It asks about what is "fair" in terms of the actions that businesses and individuals take in their attempts to make money. As the link below says, the major question is this:
How do businesses determine what is appropriate or ethical conduct for any given commercial task?
There are many theories of business ethics.