1. the branch of philosophy that investigates both the content of moral judgments (i.e., what is right and what is wrong) and their nature (i.e., whether such judgments should be considered objective or subjective). The study of the first type of question is sometimes termed normative ethics and that of the second metaethics. Also called moral philosophy.

2. the principles of morally right conduct accepted by a person or a group or considered appropriate to a specific field. In psychological research, for example, proper ethics requires that participants be treated fairly and without harm and that investigators report results and findings honestly. See code of ethics; professional ethics; research ethics. —ethical adj.