N.H. Rev. Stat. Ann. § 461-A:20

Any provision of law that refers to the "custody" of minor children shall mean the allocation of parental rights and responsibilities as provided in this chapter. Any provision of law which refers to a "custodial parent" shall mean a parent with 50 percent or more of the residential responsibility and any reference to a non-custodial parent shall mean a parent with less than 50 percent of the residential responsibility.