1. An apparatus in which environmental conditions, such as temperature and humidity, can be controlled, often used for growing bacterial cultures, hatching eggs artificially, or providing suitable conditions for a chemical or biological reaction.
2. Medicine. An apparatus for maintaining an infant, especially a premature infant, in an environment of controlled temperature, humidity, and oxygen concentration.
3. A place or situation that permits or encourages the formation and development, as of new ideas: a college that was an incubator of new approaches to sociology.

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.