The meaning of ON LINE is in or into operation. How to use on line in a sentence. When you're online, you are using a computer or other device that's connected to the Internet. If someone asks if you're online, they're wondering whether you have Internet access. The city libraries are all online. He likes to engage in online chats/discussions. I went online to do a search for information about new cars. She spends a lot of her free time online. When a device is online, it is powered on and connected to a network, other devices, or the internet. The term applies to various electronics, including computers, smartphones, smart TVs, gaming consoles, and IoT devices. ONLINE definition: 1. Online products, services, or information can be bought or used on the internet: 2. relating to…. Learn more. Play free online games at Poki, the 1 website for instant web games. Explore exclusive titles, popular favorites, and new game releases every day - no download needed! Play free online games at CrazyGames, the best place to play high-quality browser games. We add new games every day. Have fun!.