Wiki definition (for want of any other)
Altruism or selflessness is the principle or practice of concern for the welfare of others. It is a traditional virtue in many cultures and a core aspect of various religious traditions, though the concept of “others” toward whom concern should be directed can vary among cultures and religions. Altruism or selflessness is the opposite of selfishness.
Altruism can be distinguished from feelings of duty and loyalty. Altruism is a motivation to provide something of value to a party who must be anyone but one’s self, while duty focuses on a moral obligation towards a specific individual (e.g., a god, a king), or collective (e.g., a government). Pure altruism consists of sacrificing something for someone other than the self (e.g. sacrificing time, energy or possessions) with no expectation of any compensation or benefits, either direct, or indirect (e.g., receiving recognition for the act of giving).
Much debate exists as to whether “true” altruism is possible. The theory of psychological egoism suggests that no act of sharing, helping or sacrificing can be described as truly altruistic, as the actor may receive an intrinsic reward in the form of personal gratification. The validity of this argument depends on whether intrinsic rewards qualify as “benefits.”
The term altruism may also refer to an ethical doctrine that claims that individuals are morally obliged to benefit others. Used in this sense, it usually contrasted to egoism, which is defined as acting to the benefit of one’s self.