Vendorware is any software or application that is built, sold and maintained by an IT service provider or independent software vendor (ISV) firm. This is proprietary software that is commercially available under a vendor’s brand and company name.
Vendorware is also known as vendor software or commercial off-the-shelf software (COTS).
Techopedia explains Vendorware
Vendorware is any software application that is built outside the firm that consumes it. Typically, vendorware is packaged software that is designed and developed around a specific business process, such as accounting, payroll, inventory or enterprise resource planning (ERP). This software is provided to the user under an agreed license. Vendorware often requires that an organization buy a license for each machine or user. Because these are copyrighted and licensed products, vendorware cannot be altered or modified by users.