The term "vitamin D" refers to several different forms of this vitamin. ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3). Vitamin D2 synthesized by plants. Vitamin D3 is synthesized by...
The D stands for nothing. It was discovered 4th after A, B, C and hence they named it as D.
To get Vitamin D, spend some time in the sun, take some Vitamin D supplements, or eat Vitamin D rich foods, like raw catfish.
All the Vitamin D you need can be received through 15 minutes of sunlight a day.
Vitamin D (disambiguation).