Leg is the Latin root word meaning law.
An allegation is a claim that someone has done something that is against the law.
A legacy is what is left behind after someone dies in accordance to the law - a gift or inheritance. Over time, we have included reputation to be included in a person's legacy.
A privilege is a right that is guaranteed by law. This has extended to not just by government law but also school law, parental law, and social law.