A nest was a place created by animals and some other lifeforms to breed and raise their young.
Female Drayjin could be very aggressive when protecting their nests. (ENT: "Rogue Planet")
Cardassian voles were known to live in nests and create secondary nests, too. (DS9: "Ferengi Love Songs")
As a starving homeless child, Madred scavenged for taspar eggs to eat, straight from the shell, when he found them in a nest in a burned-out building. (TNG: "Chain Of Command, Part II")
In 2372, the crew of the USS Voyager discovered large eggs in a nest on the surface of the planet Hanon IV. (VOY: "Basics, Part II")
When Captain Kathryn Janeway asked a holographic Leonardo da Vinci what he imagined his life would be like if he were a sparrow, he replied that he'd make his home in a tree, in the branch of an elm and would hunt insects for food, straw for his nest and in the springtime he would sing for a companion. (VOY: "Concerning Flight")