It is a portmanteau of the term development and the word operations. Essentially, it applies the principles of agile software development to the world of software development and IT professionals.
Think of DevOps this way – a team of enterprise architects, software developers, and testers must contact a person who runs the actual server to test out the system.
The people who control the servers usually had the title of systems operations somewhere in their title. Rather than viewing these as competing groups, DevOps posits that they can work together to generate solutions.
Traditionally, a software developer would not enter the realm of the sever closet.