d3

D3 commonly refers to two distinct topics in different fields. In health and nutrition, D3 denotes vitamin D3, also known as cholecalciferol. It is produced in the skin when exposed to ultraviolet B radiation from sunlight and can be obtained from certain foods and dietary supplements. D3, together with vitamin D2, forms the two major dietary vitamins D. After intake, D3 is converted in the liver to calcifediol and then in the kidneys to calcitriol, the active hormone. Calcitriol regulates calcium and phosphate metabolism, supporting bone mineralization and immune function. Vitamin D deficiency can lead to rickets in children and osteomalacia in adults; supplementation is used to treat deficiency and to maintain bone and overall health. D3 status is commonly measured as 25-hydroxyvitamin D in blood tests.

In information technology and data visualization, D3 refers to D3.js. D3, short for Data-Driven Documents, is a JavaScript library for creating dynamic, interactive data visualizations on the web. Initially developed by Mike Bostock, D3 binds data to the Document Object Model (DOM) and applies data-driven transformations to the document. It supports SVG, HTML, and Canvas rendering and provides components for scales, axes, shapes, force layouts, transitions, and event handling. D3 is not a charting library out of the box; it offers building blocks that developers combine to produce custom visuals, from simple bar charts to complex interactive dashboards. It remains widely used in data journalism, research, and analytics for its flexibility and adherence to web standards.