(1) The term insurance means National Service Life Insurance.

(2) The terms widow or widower mean a person who was the lawful spouse of the insured at the maturity of the insurance.

(3) The term child means a legitimate child, an adopted child, and, if designated as beneficiary by the insured, a stepchild or an illegitimate child.

(4) The terms parent, father, and mother mean a father, mother, father through adoption, mother through adoption, persons who have stood in loco parentis to a member of the military or naval forces at any time before entry into active service for a period of not less than one year, and a stepparent, if designated as beneficiary by the insured.