incubate

Etymology

From Latin incubātus, past participle of incubō (“to hatch”), from in- (“on”) + cubō (“to lie”).

verb

1. (transitive) To brood, raise, or maintain eggs, organisms, or living tissue through the provision of ideal environmental conditions.
   The places where the birds are nesting are interesting spots to visit. Both parents incubate and the scene is animated as the birds fly about in all directions. 1907, “Nesting Habits of the Passenger Pigeon”, in W. B. Mershon, editor, The Passenger Pigeon
   Part of our problem in praying for our children, he suggested, is the time lage, the necessary slow maturation of our prayers. But that's the way of God's rhythm in nature. For instance, the hen must patiently sit on her eggs to incubate them before the baby chicks hatch. 1975, Catherine Marshall, Adventures in Prayer, New York: Ballantine Books, page 46
   The female cichlid fish are called "mouth breeders," which means they incubate eggs in their mouth. 2004, A. J. Jacobs, The Know-It-All: One Man's Humble Quest to Become the Smartest Person in the World, New York: Simon & Schuster, page 50
2. (transitive, figurative) To incubate metaphorically; to ponder an idea slowly and deliberately as if in preparation for hatching it.
   When you've got your theme–let the concept incubate. Walk around with it, sleep on it. 1992, Sheila Davis, The Songwriters Idea Book: 40 Strategies to Excite Your Imagination, Help You Design Distinctive Songs, and Keep Your Creative Flow, Cincinnati: Writer's Digest Books, page 96