a person who gives some of their blood or a part of their body to help someone who is ill

a blood donor 献血者

a kidney donor 肾脏捐献者

a person who gives money or goods to an organization

Thanks to a large gift from an anonymous donor, the charity was able to continue its work. 多亏得到了一位匿名人士的大笔捐助，该慈善机构才得以继续运转。