'XML (eXtensible Markup Language)' is a versatile and structured data format widely utilized in the realm of web development. Its applications are diverse, ranging from data storage and transfer to configuration settings. The dual nature of XML, being both human-readable and machine-readable, makes it suitable for various uses, including web services and data exchange processes.

Conceived in the late 1990s by the World Wide Web Consortium (W3C), XML was designed to facilitate easy data sharing across different systems, especially over the internet. Distinct from HTML's focus on data presentation, XML centers on the data's structure and content. Its foundational principles emphasize ease of use, general applicability, and effective functionality across web-based platforms.

XML is characterized by its self-descriptive nature, where tags not only denote data but also define its structure. This feature ensures consistent data processing and interpretation across varied applications. XML is integral to numerous web-based technologies, such as SOAP (Simple Object Access Protocol) in web services, RSS feeds for content dissemination, and configuration files for a range of software solutions.

The adaptability and scalability of XML have cemented its role in representing intricate data structures, particularly in web services, and as a means for data exchange between disparate applications. Its capability to support custom tags adds to its flexibility, allowing for tailored data structuring and definition.

In summary, the significance of XML in contemporary web development spans from straightforward data storage applications to complex business processes. Its capacity to organize data in a format that is both human-friendly and machine-readable positions it as an essential resource in various scenarios, encompassing web services, software configuration, and beyond.