"Постійна" is a term that can refer to a constant or an unchanging value in various fields, such as mathematics and physics. In mathematics, it often denotes a fixed number that does not vary, like the value of π or e. In physics, it can refer to constants like the speed of light or gravitational constant, which are essential for understanding the laws of nature. In a broader context, "Постійна" can also describe something that remains stable over time, such as a permanent job or a long-term relationship. This concept emphasizes reliability and consistency, which are important in both personal and professional settings.