If you are maternal, you are like a mother. How you define what it is to be “like a mother” is up to you, but most people think of nurturing things like chicken soup and kisses on the forehead.
The adjective maternal comes from the Latin maternus, which means “of a mother.” Many traits are labeled as maternal, including physical traits that are genetically passed on from the mother — like being color blind. A woman’s desire to have a child is called her “maternal instinct,” and if you care for other people in a nurturing way you are being maternal, even if you are not a mother. Your mother’s mother is your “maternal grandmother.”