They are exactly the same cable.
They are normal ethernet cables.
LAN Local Area Network (your internal network)
WAN Wide Area Network (Your external network ie internet modem)
The differences are between the spec of the cable used to make the cable ie Cat 5 or Cat 6. Cat 6 has a higher bandwidth and can pass signals of a higher frequent than Cat 5. The difference in price is now negligible so plump for Cat 6 if buying new cables to give a degree of future proofing.