The word strand has two main meanings:

1. A single thin piece of something longer, like one thread in a rope or one hair on your head. When you braid hair, you weave three strands together. A strand of spaghetti is one individual noodle. DNA, which carries genetic information in your cells, has two strands twisted together in a spiral. Scientists studying spider silk examine individual strands to understand what makes them so strong.
2. To leave someone stuck in a place with no way to leave. When a broken-down car strands a family on a desert highway, they're stuck there until help arrives. In adventure stories, characters often get stranded on islands after shipwrecks. You might feel stranded at school if you miss your bus and have no way to get home. Being stranded combines helplessness with isolation, that unsettling feeling of being somewhere you can't get away from on your own.