What _ means
A lone underscore is ambiguous; don't assume annoyance. If the entire reply is _, ask what they meant. In alex_smith, the underscore—also called an underbar—simply separates the name's parts.
Read text faces as a whole. In 2026, underscore mouths appear in expressions such as -_- (unimpressed) and ^_^ (happy). The eyes do much of the emotional work.
What does a leading underscore mean?
In code, it can signal a name intended for internal use. A name such as _cache may warn programmers not to use it from outside that code. Enforcement depends on the programming language: _ is not a universal privacy lock.
Between words, it makes code names such as snake_case readable without spaces. Underscores also appear in filenames and web addresses; not every filename must avoid spaces. Keep underscores intact when using an exact name or address.
Don't confuse it with
2Combination ideas
2Questions people ask
1Is underscore the same as underline?
No. An underscore sits beside other characters; underline is formatting beneath text. To underline a word, use formatting, not a row of underscores.
How to type _
_\005FCodes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.