underscore

higher level
| subject: SCRIPT AND NEWSPAPER
the ​character _ on a ​computer ​keyboard, used to ​draw a ​line under a ​letter or word, and also used in ​file ​names where a ​space is not ​allowed
/ˈʌn.də.skɔːr/
Valid characters for folder/file names are letters A-Z (all caps), numbers 0-9, and ‘_’ (underscore).
podkreślnik
go back to this subject's entries