Deontological ethics or deontology (from Greek deon, "obligation, duty"; and -logia) is the normative ethical position that judges the morality of an action based on the action's adherence to a rule or rules.
Deontology \De`on*tol"o*gy\, n. [Gr. ? gen. ?, necessity, obligation (p. neut. of ? it is necessary) + -logy.] The science which relates to duty or moral obligation. --J. Bentham. [1913 Webster]
Utilitarianism is a theory in normative ethics holding that the proper course of action is the one that maximizes utility, specifically defined as maximizing happiness and reducing suffering.
utilitarianism n : doctrine that the useful is the good; especially as elaborated by Jeremy Bentham and James Mill; the aim was said to be the greatest happiness for the greatest number
Utilitarianism \U*til`i*ta"ri*an*ism\, n. 1. The doctrine that the greatest happiness of the greatest number should be the end and aim of all social and political institutions. --Bentham. [1913 Webster] 2. The doctrine that virtue is founded in utility, or that virtue is defined and enforced by its tendency to promote the highest happiness of the universe. --J. S. Mill. [1913 Webster] 3. The doctrine that utility is the sole standard of morality, so that the rectitude of an action is determined by its usefulness. [1913 Webster]