The characters combine with perfect logic: 用户 (yònghù) is the standard word for “user.” Adding 名 (míng) specifies that we are talking about the *name* of that user. So, `yònghù míng` = User's Name.
While “用户名” itself is a modern, universal concept, its application in China has unique cultural and practical dimensions. In the West, usernames are often creative, anonymous handles designed to express personality while protecting one's real identity. In China, while creative names exist, there's a much stronger trend towards pragmatic and identity-linked usernames. The most significant difference is the prevalence of using one's mobile phone number (手机号 - shǒujī hào) as the primary `用户名`. This is tied to the nationwide policy of 实名认证 (shímíng rènzhèng), or “real-name authentication.” Most major online services in China (like WeChat, Alipay, Taobao) are required to link accounts to a real person's government-issued ID. Using a phone number, which is already linked to one's ID upon purchase, is the most efficient way to do this. For a learner, this means when a Chinese app asks for your `用户名`, it may very well be expecting you to type in your 11-digit phone number, not a creative handle like “DragonSlayer99.” This reflects a different cultural approach to online identity—one that is less about anonymity and more about accountability and integration with real-life services.
“用户名” is used in any context involving logging into a digital service. It's a neutral, standard term you will see on every registration and login page.