The Collaborative International Dictionary of English v.0.48:
Incubation \In`cu*ba"tion\, n. [L. incubatio: cf. F.
1. A sitting on eggs for the purpose of hatching young; a
brooding on, or keeping warm, (eggs) to develop the life
within, by any process. --Ray.
2. (Med.) The development of a disease from its causes, or
its period of incubation. (See below.)
3. A sleeping in a consecrated place for the purpose of
dreaming oracular dreams. --Tylor.
4. The maintenance (of a living organism, such as
microorganisms or a premature baby) in appropriate
conditions, such as of temperature, humidity, or
atmospheric composition, for growth.
5. The gradual development in some interior environment,
until fully formed; as, the incubation time for developing
a new drug may be longer than ten years from its first
Period of incubation, or Stage of incubation (Med.), the
period which elapses between exposure to the causes of an
infectious disease and the attack resulting from it; the
time during which an infective agent must grow in the body
before producing overt symptoms of disease.
[1913 Webster +PJC]