donor

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. One that contributes something, such as money, to a cause or fund.
2. n. Medicine An individual from whom blood, tissue, or an organ is taken for transfusion, implantation, or transplant.
3. n. Chemistry An atom, molecule, or ion that provides a part to combine with an acceptor, especially an atom that provides two electrons to form a bond with another atom.
4. n. Electronics An element introduced into a semiconductor with a negative valence greater than that of the pure semiconductor.
5. adj. Medicine Used for transfusion, implantation, or transplant: a donor organ.

Century Dictionary and Cyclopedia

1. n. One who gives or bestows; one who confers anything gratuitously; a benefactor.
2. n. Specifically, in law: A giver.
3. n. One who creates an estate tail.
4. n. One who gives to another a power. See power.

Wiktionary

1. n. One who donates, typically, money.

GNU Webster's 1913

1. n. One who gives or bestows; one who confers anything gratuitously; a benefactor. Inverse of recipient.
2. n. (Law) One who grants an estate; in later use, one who confers a power; -- the opposite of donee.

WordNet 3.0

1. n. (medicine) someone who gives blood or tissue or an organ to be used in another person (the host)
2. n. person who makes a gift of property