deontology

"Philosophy for Beginners" を読んでいます。
To help decide if an action is right or wrong, philosophers have developed ways of looking at morality. Some have very formal names, such as utilitarianism, deontology and virtue ethics.

"ontology" と同様に哲学用語でしょうね。
・Collins Dictionary: the branch of ethics dealing with duty, moral obligation, and moral commitment: As stated before, deontology focuses on adhering to ethical duties, while consequentialism focuses on the outcomes (consequences) of actions.
・Wikipedia (excerption): In moral philosophy, deontological ethics or deontology is the normative ethical theory that the morality of an action should be based on whether that action itself is right or wrong under a series of rules and principles, rather than based on the consequences of the action

"ontology" との関係がよく分かりませんね。