WiFi extenders and WiFi boosters are sometimes-interchangeable terms for an older networking tech designed to complement a router. These network enhancements take an existing WiFi signal from a router and, as the name implies, extend or boost its range.  Mesh WiFi simplifies the process of having wider-reaching wireless with a single SSID login (one username and password) for the entire home, and provides expanded coverage because each device in the network emitting its own independent signal.