closed source

British  

noun

1. 1. intellectual property, esp computer source code, that is not made available to the general public by its creators

   2. ( as modifier ) Compare open source

      closed source software

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Example Sentences

She claims it is one of the most effective tools to fight against China’s firewall, despite criticism from experts who warn that since Ultrasurf is closed source, there is no way to independently verify its performance or assure end users that they are not being tracked.

From New York Times

“Open source versus closed source, we don’t get hung up on those things,” Ms. Swett said.

From New York Times

Here, industry shifted from a single internal or closed source of research to multiple external or open sources18.

From Nature

It’s contrasted with “closed source” or “proprietary” code, which a company guards closely as a trade secret.

From The Verge

"We also said that, as an app provider, we value the ongoing stability and compatibility of operating systems, whether they are 'open source' or 'closed source'," the spokesman said.

From Reuters