A landing page might also be called a “sales page” or a “squeeze page”, depending on how it’s used.

A landing page generally refers to a single page that is meant to sell a product/service/event right on that page, or to get a user to opt-in to an email list or newsletter. The entire page is meant to keep a person on that page and to complete the action on that page.

Squeeze pages refer specifically to a page that drives opt-ins.

Note: While there are certain standards and practices that a lot of marketers use, landing pages can look very different and there is no single right way to write copy for or design a landing page.
Warning: Some folks incorrectly refer to the homepage of a website as a “landing page”. In a broad way, that makes sense – people “land” on the homepage when they come to the site (or any page for that matter). However, in the world of marketing, keep in mind that a “landing page” refers to something very specific.