The phrase "defunct company" refers to a business organization that is no longer functioning or operating. It means that the company has closed down or gone out of business. Full definition
The now defunct company become popular from its name on the monopoly board game. (autoinsuresavings.org)
Audible has announced that they have purchased 5,000 audio editions from the now defunct company. (goodereader.com)
There are already thriving communities for comic - book piracy --- in a given week, they scan and disseminate almost every book that hits shelves (they also preserve out - of - print orphaned works from defunct companies). (washingtoncitypaper.com)