رجوع كنيد به "واژه نامه فيزيك" مركز نشر دانشگاهي

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Note added at 35 mins (2007-04-27 12:28:59 GMT)
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A solstice occurs twice a year, whenever Earth's axis tilts the most toward or away from the Sun, causing the Sun to be farthest north or south at noon. The name is derived from Latin sol (sun) and sistere (to stand still), because at the solstice, the Sun stands still in declination, that is, it reaches a maximum or a minimum. The term solstice can also be used in a wider sense as the date (day) that such a passage happens. The solstices, together with the equinoxes, are related to the seasons. In some languages they are considered to start or separate the seasons; in others they are considered to be center points (in English, in the Northern hemisphere, for example, the period around the June solstice is known as midsummer, and Midsummer's Day is the 24 June — now two or three days after the solstice).

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Note added at 55 mins (2007-04-27 12:49:13 GMT)
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We also have equinox as زمان اعتدال
رجوع كنيد به واژه نامه ژئوفيزيك و هواشناسي مركز نشر دانشگاهي