Responsive design

noun

Topic: Design and layout

1. A way of building a website so that its layout adapts automatically to the screen it is viewed on, from a large desktop monitor to a small phone.
2. A large share of web traffic now comes from phones, and Google judges sites mainly by their mobile version, so a site that works badly on a small screen loses both sales and search ranking. Responsive design means one website that works everywhere, rather than a separate mobile version to maintain.

Example On the responsive version, the menu folds into a single button on a phone.

See also Accessibility Above the fold SEO