Meaning of small circles and sharps (#) in pinout diagram?
The default in logic circuits is that a high level (logic one) activates a function. The small circle denotes inversion, so we can have an external signal that is active low, which (when low) activates a function (that is still activated by the more-or-less theoretical signal after the circle, which is active high).

The fact that a signal is active low can be represented in various ways in the signal name, the # is one, and _ is another.

Don't be confused by the location of the symbol name, it denotes the external signal, not the internal signal after the inversion.