A landing page is a webpage which centres around getting a visitor to enter their details into a form. It aims to convert leads into sales – visitors enter in their information and the website provides them with something in return [e.g. an e-newsletter subscription or discount].
For a webpage to be a landing page it must contain a form and there must be a concentration on gathering information from visitors [through the form].
A landing page generally has minimal distractions. There is usually some writing [copy] but it is organised so that the form is highlighted and easy to see and read.