Pod has several meanings:

1. A long shell or case that holds seeds, especially in plants like peas or beans. When you shell peas for dinner, you're opening the pod to get the peas inside. A pea pod starts green and plump, then dries and splits open when the seeds are ready. Many plants, from vanilla orchids to milkweeds, grow their seeds in pods.
2. A group of whales or dolphins swimming together. Scientists who study marine life might spot a pod of orcas hunting cooperatively near Alaska, or a pod of dolphins leaping through ocean waves. These pods are like whale families, with members communicating through clicks and whistles as they travel and hunt together.
3. A small, enclosed space or compartment. Modern offices sometimes have sleeping pods where tired workers can take naps, and some futuristic trains have passenger pods. The word suggests something compact and self-contained, like its own little world.
4. A detachable section of a spacecraft or aircraft. An escape pod in science fiction movies is a small emergency vessel that separates from the main ship during danger.