Uttarayana
The term Uttarāyaṇa (commonly Uttarayanam) is derived from two different Sanskrit words – "uttaram" (North) and "ayanam" (movement) – thus indicating the northward movement of the Sun. In the Gregorian calendar, this pertains to the "actual movement of the sun with respect to the earth." It is also known as the six-month period that occurs between the winter solstice and the summer solstice (approximately 20 December - 20 June).