motivation based on ideas of right and wrong
"Her decision to return the lost wallet was driven entirely by her personal ethics regarding honesty."
the philosophical study of moral values and rules
"The university hired a professor to teach ethics, introducing students to the complex philosophical study of moral values and rules that govern professional conduct."
The study of principles relating to right and wrong conduct.
"The university hired a new professor specifically to teach ethics, focusing on how students can distinguish between right and wrong in complex situations."
In plain English: Ethics are the rules about what is right and wrong that people agree to follow.
"The company faced criticism for ignoring its own ethical standards regarding worker safety."
Usage: Use "ethics" to refer to the moral principles that govern a person's behavior or the conducting of an activity. It describes the rules about what is right and wrong rather than the academic study of those rules.
The word ethics comes from the Ancient Greek ethos, meaning "character" or "moral nature." It traveled through Late Latin and French into Middle English before entering modern usage.