A local area network (LAN) is a computer network that interconnects computers within a limited area such as a residence, school, laboratory, university campus. A WAN connects different smaller networks, including local area networks (LAN) and metro area networks (MAN).
LAN means Local Area Network (i.e. a limited small area, for e.g., a computer lab) whereas WAN means Wide Area Network (i.e. a wide area such as the world, for e.g. internet).
LAN is local area network. It is used to connect devices in local network. WAN is wide area network. It is used to connect in a wide area like across cities.