Definition LAN :
Also Known As: local area network
A LAN supplies networking capability to a group of computers in close proximity to each other such as in an office building, a school, or a home. A LAN is useful for sharing resources like files, printers, games or other applications. Most LANs are built with relatively inexpensive hardware such as Ethernet cables, network adapters, and hubs. Wireless LAN and other more advanced LAN hardware options also exist. Specialized operating system software may be used to configure a LAN. For example, most flavours of Microsoft Windows provide a software package called Internet Connection Sharing (ICS) that supports controlled access to LAN resources. The term LAN party refers to a multiplayer gaming event where participants bring their own computers and build a temporary LAN.
Examples: The most common type of LAN is an Ethernet LAN. The smallest home LAN can have exactly two computers; a large LAN can accommodate many thousands of computers. Many LANs are divided into logical groups called subnets. An Internet Protocol (IP) "Class A" LAN can in theory accommodate more than 16 million devices organized into subnets.

Definition Ethernet :
is a physical and data link layer technology for local area networks (LANs). Ethernet was invented by engineer Robert Metcalfe. When first widely deployed in the 1980s, Ethernet supported a maximum theoretical data rate of 10 megabits per second (Mbps). Later, Fast Ethernet standards increased this maximum data rate to 100 Mbps. Today, Gigabit Ethernet technology further extends peak performance up to 1000 Mbps. Higher level network protocols like Internet Protocol (IP) use Ethernet as their transmission medium. Data travels over Ethernet inside protocol units called frames. The run length of individual Ethernet cables is limited to roughly 100 meters, but Ethernet can be bridged to easily network entire schools or office buildings.
Definition IP :
is probably the world's single most popular network protocol. Data travels over an IP-based network in the form of packets; each IP packet includes both a header (that specifies source, destination, and other information about the data) and the message data itself. IP supports the notion of unique addressing for computers on a network. Current IP (IPv4) addresses contain four bytes (32 bits) that is sufficient to address most computers on the Internet.
IP supports protocol layering as defined in the OSI reference model. Popular higher-level protocols like HTTP, TCP, and UDP are built directly on top of IP. IP originated with UNIX® networking in the 1970s.
Definition ICS :

Microsoft developed ICS as part of Windows 98 Second Edition. The feature has been included as part of all subsequent Windows releases, but it is not available as a separate installable program.
ICS follows a client/server model. To set up ICS, one computer must be chosen as the server. The designated computer must support two network interfaces, one directly connected to the Internet and the other connected to the remainder of the LAN. In a traditional home dial-up network, for example, the server computer is directly connected to the modem.

Wired vs. Wireless
WiredWireless
Installationmoderate difficultyeasier, but beware interference
Costlessmore
Reliabilityhighreasonably high
Performancevery goodgood
Securityreasonably goodreasonably good

In which case Installation is easier?
Which of these networks is cheaper?
Which network is more reliable?
Performance is higher in wired or wirwlsess?
And security is same in both cases!!!