tissue culture

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The technique or process of maintaining or cultivating cells or tissues derived from a living organism in a culture medium.
• noun A culture of cells or tissue grown by this technique or process.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun the process or technique of propagating tissue (either cells or plants) in a culture medium
• noun the culture of tissue grown by this process