Final answer:
The ethical principle often referred to as the "greatest happiness principle" is the Principle of Utility. It focuses on maximizing happiness or utility for the greatest number of people.
Step-by-step explanation:
The ethical principle often referred to as the "greatest happiness principle" is the Principle of Utility. This principle, developed by Jeremy Bentham and later modified by John Stuart Mill, states that actions are right in proportion as they tend to promote happiness and wrong as they tend to produce the reverse of happiness. It focuses on maximizing happiness or utility for the greatest number of people. Mill argued that the morally right action is the one that produces the most net happiness.