A land-line (or fixed line) phone is a phone (and phone number) that is physically and directly connected to a telephone network.
A mobile (cellular) is not a land-line phone – it connects wirelessly to a mobile phone network through a cellular tower.
A VoIP phone is not a land-line phone – it connects to the phone network by connecting to the internet.
A satellite phone is not a land-line phone – it connects to the phone network through a satellite connection.
A cordless phone is usually a land-line phone – it connects to the cordless base station which then connects to the land-line connection.