The term ONE ONLINE can be broken down into two crossword solutions: USER (4 letters) and ONE (3 letters). The term USER refers to someone who uses a computer or other electronic device to access the internet. This person is typically referred to as an online USER, or someone who is connected to the internet. The term ONE refers to a single entity, such as a website, application, or service that is available on the internet. Together, the two terms refer to a single online entity, such as a website, application, or service that is available for use by an online USER.