What Does Wi-Fi Range Extender Mean?
A Wi-Fi range extender is a device between a base router, or wireless local area network (LAN) access point, and a client computer or device that is outside the signal range or blocked by a signal barrier. The extender works as a wireless relay or repeater by receiving access point signals, which are retransmitted to the client.
This term is also known as range expander.
Techopedia Explains Wi-Fi Range Extender
The computer or device using a Wi-Fi range extender experiences a latency increase, that is, delay time when sending and receiving signals. The thinking is that clients that receive weak access point signals find Wi-Fi range extenders more effective than clients unable to receive any signal at all.