Sentence:  Deontology is derived from the Greek words, το δεον (that which is proper) and Λογια, knowledge — meaning the knowledge of what is right and proper; and it is here specially applied to the subject of morals, or that part of the field of action which is not the object of public legislation. As an art, it is the doing what is fit to be done; as a science, the knowing what is fit to be done on every occasion." <WSD>Deontology</WSD> or, The science of morality : in which the harmony and co-incidence of duty and self-interest, virtue and felicity, prudence and benevolence, are explained and exemplified 
Meaning of the word marked with <WSD> tags:  Ethics. (from c. 1826)