I think that the word "morality" (also "ethics") is, to a truly ridiculous extent, not well-defined.Or rather, people are dreadfully inconsistent about what they call morality. I can give you a definition of ethics, morality is trickier so I may be able to only summarize a few points.
Ethics is a system of determining right action for individuals and groups of individuals from a set of commonly held values. For example: if equity is a value, then preferential treatment becomes a wrong. Ethics works by finding common values and working from them. The fact that value is subjective has no bearing; ethical systems merely look for a common denominator and work from there. Different ethical systems are the product of applying different philosophical methodologies to different values sets.
Morality is very different. It is the object of the assumption that there is a universal set of rules and values to which all human beings must, for some reason or other, assent. What this universal code consists of, isn't necessarily universally accepted, but what is universally accepted, or nearly so, is the assumption that there is a universal code. That a physicalist, or mechanistic account of the universe cannot account for this is evident. That very few human beings actually accept a physicalist or mechanistic worldview, even if they claim to do so, is also evident. It presupposes some kind of telos, or universal purpose.
So what morality is, is this: an objective standard of behavior that is (instinctualy) assumed by everybody, agreed (in total; the vast majority hold a large number of principles in common and differ only on application, hence the need for ethics) upon by few, and can only be fully accounted for by some kind of metaphysics.
Edit: spelling and word usage