[{"Bold_text": "noun", "List Items": ["a person or thing occurring singly, especially an individual set apart from others.", "a child or animal that is the only one born at one birth:a research program involving twins and singletons.an only child in a family.", "a child or animal that is the only one born at one birth:a research program involving twins and singletons.", "an only child in a family.", "Chiefly British.an unmarried person; a single.", "Cards.a card that is the only one of a suit in a hand.", "Mathematics.a set consisting of one given element."]}]