Prepare yourselves, this one is a doozy.
Right and Wrong, are two very objective concepts, and the conflict between what makes something Good and what makes something Bad is known as Morality. Conscience is having the ability to make decisions around Morality based off of one’s own Moral Compass. There are rules that must be taken into account when making moral decisions, often revolving around the objective states of certain subjects. A lot of these subjects involve the effects that ones actions will have on those around them. To have Conscience is to be able to acknowledge those around you and how your decisions may affect them.