[{"Bold_text": "noun", "List Items": ["the melting of a significant portion of a nuclear-reactor core due to inadequate cooling of the fuel elements, a condition that could lead to the escape of radiation.", "a quickly developing breakdown or collapse:a bond-market meltdown;the meltdown of a marriage.", "Informal.a sudden loss of control over one’s feelings or behavior:My toddler had a meltdown when I tried to leave the house."]}]