The word hatch has several related meanings:

1. To emerge from an egg. When a baby bird hatches, it breaks through its shell and comes into the world. Chickens hatch from eggs after about 21 days, while sea turtles take about two months. The moment of hatching is dramatic: the baby animal uses a special egg tooth or beak to crack the shell from the inside, then pushes its way out into a brand new life.
2. To keep eggs warm until they hatch. A mother hen hatches her eggs by sitting on them, using her body heat to help the chicks develop inside. This process is also called incubation. Farmers sometimes use special heated boxes called incubators to hatch eggs when they don't have enough hens.
3. To create or develop a plan, often secretly. When you hatch a plan or hatch a scheme, you're carefully working out the details of something you want to do. You might hatch a plan to surprise your best friend on their birthday, or siblings might hatch a scheme to convince their parents to get a puppy. The word suggests careful planning, and sometimes carries a hint of secrecy or mischief.

As a noun, a hatch can also mean an opening or door, especially on a ship or spacecraft, like when astronauts open the hatch to exit their vessel.