Microsoft Design Language, previously known as Metro, is a design language created by Microsoft. This design language is focused on typography and simplified icons, absence of clutter, increased content to chrome ratio, and basic geometric shapes. Early examples of MDL principles can be found in Encarta 95 and MSN 2.0. The design language evolved in Windows Media Center and Zune and was formally introduced as Metro during the unveiling of Windows Phone 7. It has since been incorporated into several of the company's other products, including the Xbox 360 system software and the Xbox One system software, Windows 8, Windows Phone, and Outlook.com. Before the "Microsoft design language" title became official, Microsoft executive Qi Lu referred to it as the modern UI design language in his MIXX conference keynote speech. According to Microsoft, "Metro" has always been a codename and was never meant as a final product, but news websites attribute this change to trademark issues.

Microsoft Corporation is an American multinational corporation and technology company headquartered in Redmond, Washington. Microsoft's best-known software products are the Windows line of operating systems, the Microsoft 365 suite of productivity applications, and the Edge web browser. Its flagship hardware products are the Xbox video game consoles and the Microsoft Surface lineup of touchscreen personal computers. Microsoft ranked No. 14 in the 2022 Fortune 500 rankings of the largest United States corporations by total revenue; and it was the world's largest software maker by revenue in 2022 according to Forbes Global 2000. It is considered one of the Big Five American information technology companies, alongside Alphabet, Amazon, Apple, and Meta.