An incubator is a device that's basically a warm box, meant for keeping premature babies safe and cozy. Sometimes very tiny infants need to spend a little time in an incubator before they're ready to leave the hospital.
Incubators are used in hospitals, but you'll also find them on farms, where they keep eggs warm before they hatch, and then protect the baby chicks. A biologist uses another type of incubator, one that controls the temperature for growing microbes or cells in a lab. Because all incubators help something grow and develop, businesspeople also use the term to mean a place or equipment that's available to help a new business get off the ground or grow larger.