Vitamin D is known as the "sunshine vitamin" because it is synthesized in the skin upon exposure to sunlight, specifically ultraviolet B (UVB) rays. This unique capability makes it different from most other vitamins, which must be obtained primarily through diet. Vitamin D plays a vital role in calcium absorption and bone health, contributing to the maintenance of strong bones and teeth. It also supports the immune system, cell growth, and overall health. Lifestyle factors such as geographic location, skin pigmentation, and sun exposure can influence vitamin D levels, making awareness of this vitamin's importance essential for overall well-being.