The core or central part of something that is undergoing freezing, often used in scientific contexts such as in meteorology or physics.

जमने वाला केन्द्र

English Usage: The freezing nucleus in the supercooled water droplets caused them to freeze instantly when they were disturbed.

Hindi Usage: जब सुपरकोल्ड पानी की बूँदों को हिलाया गया तो जमने वाला केन्द्र तुरंत जम गया।