Public-domain software is widely available for anyone to use and modify without any restrictions. However, there are several synonyms for this term that you should know if you're working in the software industry. One option is open-source software, which allows users to access and alter the code in the program. Another synonym is freeware, which refers to software that is available for free but might have certain limitations or restrictions. Shareware is another option, as it is software that is freely distributed for a trial period, after which you need to pay to continue using it. Finally, there's proprietary software, which is developed and owned by a particular company and cannot be modified or distributed freely.