For questions pertaining to ps, a command for printing information about running processes. Use this tag for questions about ps itself or questions about issues arising from using the ps command-line utility.

According to the ps(1) man page

ps (short for "process status") displays a selection of the active processes, subject to having appropriate privileges to obtain information about those processes. If you want a repetitive update of the selection and the displayed information, use instead.

Further reading

How can I prevent 'grep' from showing up in ps results?

Why does `htop` show more process than `ps`

What does aux mean in `ps aux`?

External References

ps specification (The Open Group Base Specifications Issue 7, 2018 edition)

ps article in Wikipedia