A carrier is someone or something that transports things from one place to another. A mail carrier delivers letters and packages to your neighborhood. An aircraft carrier is a massive warship that carries planes across the ocean and serves as a floating runway. A baby carrier is a special backpack or wrap that lets parents carry their infant hands-free.

The word also describes someone who has a disease but doesn't get sick from it, yet can still spread it to others. During a flu outbreak, a carrier might feel perfectly healthy but unknowingly pass the virus to classmates. This meaning became especially familiar during recent disease outbreaks, when people learned they could be carriers without showing any symptoms.

In another sense, a carrier transports signals: your phone's cellular carrier (like Verizon or T-Mobile) carries your calls and text messages through networks of towers and satellites.

What connects these meanings is the idea of holding and moving something, whether it's mail, airplanes, germs, or invisible phone signals. The carrier itself might not change, but it moves important things where they need to go.