1. A small pouch, often consisting of two plastic or foil sheets sealed at the edges, used to distribute single portions of products in the form of liquids, powders, or small pieces: a ketchup packet.

2. A small package or bundle: sent me a packet of newspaper clippings.

3. Informal A sizable sum of money.

4. A boat or ship, usually a coastal or river steamer, that plies a regular route and carries passengers, freight, and mail.

5. A short block of data transmitted in a packet-switching network.