1. The place where birds lay their eggs and then take care of their young ones after they hatch: Some warblers build nests out of small twigs and grass so they can lay small round fertile objects with a shell and provide a place for their little chicks after they are born.

All flying animals don't make nests; for example, some waterfowl and a few land avifauna lay little oval reproductive elements on bare rocks of ledges that project out from the face of a cliff near oceans.

Other species of the feathered vertebrates of the class of Aves, or birds, that live in sandy areas make little or no preparation for any nests; instead, they make bowl-shaped places in the sand where they lay their eggs and after the little ones hatch, the adults feed and protect them.

Larger fowl; such as, chickens use straw and grass to produce their nests or the human owners provide the material for their nests.

2. A home or house where people live: Jane and Bob live in their little cozy nest in the suburbs.
3. A place that is filled with, or frequented by, undesirable people or things: A great deal of news has been focusing on the nests of U.S. spies that have been snooping in various countries.
4. Etymology: from Old English nest, of Germanic origin and related to Latin nidus, "nest".

1. To use or to build a place produced by a bird or another animal: Norbert has a barn where owls often nest.

Near the ocean, there is an area where seagulls are nesting by the hundreds.

2. To fit an object or objects inside a larger one or inside each other: The village is nested inside a beautiful valley.

Karen's little girl has Russian dolls made of wood carvings that nest inside each other.

Rene has sets of bowls in which smaller ones nest inside the larger ones.