An access point is a device that creates a wireless local area network (or WLAN), usually in an office or large building. An access point connects to a wired router, switch or hub via an Ethernet cable and projects a WiFi signal to a designated area. They are designed to expand the WiFi coverage you are currently receiving, these access points act as receivers and transmitters of wireless signals.
A wireless access point also known as a hotspot operating in the same way, providing network connectivity to other devices, providing network connectivity to other devices.
The wireless router in your home will already have an access point built into it, but will also work with another access point to create better internet coverage over a larger area. The access point plugs into a wired router, switch or hub, sending out wireless signals to your mobile phone, desktop, tablet and laptop. So you can access the network anywhere in your office or home.