Hotspot can be used to refer to a private mobile portable cellular device, a feature on a smartphone or a public Wi-Fi access point.
A public hotspot is usually hosted by a campground, marina, cafe or library.
A private hotspot might be one you host yourself, or one you've been given special access to such as a driveway host or business you are visiting.
A mobile hotspot or personal hotspot is the term often used to describe a private hotspot made by a smartphone or mobile hotspot device to share a cellular connection.