What are packets when talking about networking?

I found this programs about networking and it says this about packets, the problem is that I don't know what a packet or packets are?



Here is what the program says: "This application captures every packet on the wire to display important information such as a list of packet"What are packets when talking about networking?
In an IP based network, such as a LAN or the Internet, all data that is sent or received will be in the form of packets. Its a unit of data that is being sent from a source to a destination.What are packets when talking about networking?
Message ( Request) are sent over the network from one computer to the next. These messages are the visible part that humans see, but each message has other information that must be contained also. This is information on where to send it to, what route along the network and who the recipient is. It may also contain information such as, what to do if recipient is offline, etc. So you message is wrapped in this container and sent..a ccomplete message and wrapper is called a packet, and a packet can be broken apart to be assembled on the other end.