Ethics is a term that encompasses every other discipline that we study. Ethics can be defined in two broad terms. First ethics can be used to refer to some well based standards which define what is right or wrong which prescribes to us what we ought to do.
This is expressed in terms of obligations rights, fairness or to any other virtues. In normal practice, this would refer to some of the standard which imposes upon us reasonable obligations that prevent us from committing something wrong like murder, fraud, assaults, and others.