Ad Hoc Network
An ad hoc network is a temporary network created between two devices without utilizing any other networking infrastructure. These networks exist for a single session, often for a specific purpose like transferring files or sharing an Internet connection. Ad hoc networks do not require a router or wireless access point. Instead, the devices themselves route network traffic.
Ad hoc networks are often direct peer-to-peer Wi-Fi connections created between two computers or mobile devices. However, these networks are not limited to two devices. For example, a smartphone can also create an ad hoc wireless network to serve as a mobile hotspot to share its Internet connection. Multiple devices can connect to a wireless ad hoc network, though performance may degrade as additional devices are added.
Wired networks may also be considered ad hoc. A temporary network can be established between two computers using a single Ethernet cable. Two computers with Thunderbolt ports can use a Thunderbolt cable to establish a temporary connection.
NOTE: Ad hoc networks generally use a low level of security, so it's best to only use them temporarily.