1. To sit on (eggs) to provide heat, so as to promote embryonic development and the hatching of young; brood.
2. 1. To maintain (eggs, organisms, or living tissue) at optimal environmental conditions for growth and development.
   2. To maintain (a chemical or biochemical system) under specific conditions in order to promote a particular reaction.
3. To form or consider slowly and protectively, as if hatching: incubated the idea for a while, then announced it.

1. To brood eggs.
2. To develop and hatch.
3. To undergo incubation.

[Latin incubāre, incubāt-, to lie down on : in-, on; see in-² + cubāre, to lie down.]

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.