Domestic violence is a crime between family members or household members, and the state of Maine defines that as siblings, husband/wife, boyfriend/girlfriend, parent/child. That includes if you assault your girlfriend, you terrorize your parents, you threaten to hurt your spouse. Those all qualify as crimes of domestic violence.
The issue is, some crimes of domestic violence such as domestic violence assault will prohibit you federally from ever owning, using or possessing a firearm and under federal law, ammunition. That means that if you like to hunt, like a lot of folks here in Maine do, you're never going hunting again -- at least not with a firearm. If you are in need of home protection or personal protection, you're prohibited from ever using it. So there are some real consequences that accompany a domestic violence charge and a conviction that you don't face for the same charge that doesn't have in front of it the term “domestic violence.”