What's the difference between gross negligence and criminal negligence? A simple example that would show the difference would be appreciated.
Criminal negligence pertains to criminal acts, which are prosecuted by the government and where a defendant can be convicted and punished. There will be a statute explaining where "criminal negligence" is relevant and when it is applicable. Here is the section in Washington law about criminal negligence:
A person is criminally negligent or acts with criminal negligence when he or she fails to be aware of a substantial risk that a wrongful act may occur and his or her failure to be aware of such substantial risk constitutes a gross deviation from the standard of care that a reasonable person would exercise in the same situation.
There are a number of criminal offenses where being "criminally negligent" in doing the thing is sufficient, for example mistreatment of a child or manslaughter. First degree murder requires "premeditated intent to cause the death of another person" which does not does not include "criminal negligence" (there is a separate clause about "under circumstances manifesting an extreme indifference to human life" which is different from criminal negligence).
"Gross negligence" can arise in a number of other non-criminal circumstances, and is defined (and discussed) here.
Gross negligence is the failure to exercise slight care. It is negligence that is substantially greater than ordinary negligence. Failure to exercise slight care does not mean the total absence of care but care substantially less than ordinary care.
This concept arises under numerous laws such as the gross negligence of government officers in fish and wildlife matters, where the game wardn can be sued and found civilly liable for gross negligence in performance of duties. He can't be imprisoned (it's not a crime), but he can be fired or forced to compensate the damaged party.
There is no clear difference in what level of negligence we are talking about, instead the difference has to do what what kind of law we are concerned with. Usually (?), crimes are intentional acts where the prosecution has to prove that the defendant intended to do so-and-so. But laws are also written so that certain levels of bad behavior also punishable, such as tricking a person into falling to their death as part of a jackass stunt.
One use of "gross negligence" in a civil case is that certain act may be immunized against liability arising from simple negligence (Good Samaritan law for example), but not gross negligence.