Tomorrow marks the 20th anniversary of open-source software. More specifically, tomorrow marks the 20th anniversary of the term “open source.”

The phrase was coined by Christine Peterson, the cofounder and past president of the nontech public interest group Foresight Institute. After 20 years, Peterson is revealing more insight into how the use of the term open-source software began. Peterson noted there are a variety of different accounts on coining the term, but hers came from a need to make the field more accessible. 

“The introduction of the term ‘open-source software’ was a deliberate effort to make this field of endeavor more understandable to newcomers and to business, which was viewed as necessary to its spread to a broader community of users,” Peterson wrote in a blog post.

In 1997, Peterson was serving as executive director at Foresight Institute. By the end of the year, the organization was holding weekly meetings to discuss computer security and came across the idea of free software. “We had identified free software as a promising approach to improving software security and reliability and were looking for ways to promote it. Interest in free software was starting to grow outside the programming community, and it was increasingly clear that an opportunity was coming to change the world. However, just how to do this was unclear, and we were groping for strategies,” she wrote.

According to Peterson, the term free software was distracting because of its focus on price. She believed the industry needed a word that would focus on source code and not confuse people who were new to the concept. The term “open source” fulfilled those requirements, she explained.

On February 2, 1998, software developer Eric Raymond made a visit to the organization to work with Netscape on a plan to make browser code freely available under a free-software-style license. At the time, open source was still being referred to as “free software” or “source code available software,” but Peterson was focused on the need for a better term when she thought of open-source software. “While not ideal, it struck me as good enough,” Peterson wrote.

She ran the term by at least four others in the software development community, including Eric Drexler, Mark Miller and Todd Anderson, who all liked it — although a friend of Peterson’s in the marketing field commented that the term “open” had been “overused and abused” and thought there could be a better term. “He was right in theory; however, I didn’t have a better idea, so I thought I would try to go ahead and introduce it. In hindsight, I should have simply proposed it to Eric Raymond, but I didn’t know him well at the time, so I took an indirect strategy instead,” she wrote. 

On February 5, 1998 at a meeting at VA Research, Peterson embarked on proposing the term, however, she felt as a non-programmer, her influence within the software community would be weak. Among those attending the meeting was Todd Anderson, a Linux programmer and one of the first people she had run the term past earlier. During the meeting, rather than asserting that the community should use the new term, Anderson just used the word in conversation to see what would happen.

There was no response to the new term at first, and according to Peterson it seemed like she and Anderson were the only ones to notice. However, a few minutes later, another member used the word without even intending, she said.

At the end of the meeting, they discussed terminology, with some of the members endorsing “open source,” including Anderson and Eric Raymond from Netscape and author of Cathedral and the Bazaar.

By the end of February, O’Reilly and Netscape had started using the term. Eric Raymond began promoting the term to the media, while Tim O’Reilly promoted it to businesses, she said. In April, a meeting held by O’Reilly that was originally announced as the first Freeware Summit was being referred to as the first Open Source Summit.

In the months that followed, the popularity continued to grow, and today it is hard to imagine a world without the term open source.

“A quick Google search indicates that ‘open source’ appears more often than ‘free software,’ but there still is substantial use of the free software term, which remains useful and should be included when communicating with audiences who prefer it,” Peterson wrote.