The root word for Ethical is the Greek "ethos," meaning "character." The root word for Moral is Latin "mos," meaning "custom."
Both words are broadly defined in contemporary English as having to do with right and wrong conduct. Character and custom, however, provide two very different standards for defining what is right and what is wrong. Character would seem to be a personal attribute, while custom is defined by a group over time. People have character. Societies have custom. To violate either can be said to be wrong, within its appropriate frame of reference.
It is possible to draw an objective distinction between good and bad, right and wrong, which does not depend on context for a measuring stick. Let us say that good, or right, would be the quality of those things which tend toward the greatest survival for the greatest cross-section of life and bad, or wrong, would apply to those things which tend away from that greatest survival. This is a standard which can be objectively tested for, in theory.
(more to come, as time permits)