Can someone explain why Scheme's keywords have the hash: #:keyword instead of just :keyword like in Common Lisp and Elisp.

https://stackoverflow.com/questions/4873810/what-does-mean-in-lisp

Found some explanation here for Common Lisp's usage of # here.

Also, there is #t, #true, #false, #f, and so on.

#scheme #guile #emacs #commonlisp #lisp #elisp #emacslisp

What does # mean in LISP

For example, #'functionname, is it necessary?

Stack Overflow

@tusharhero from what I can find, the convention for scheme might have started with PLT scheme (racket) and adopted by other scheme implementations. Interestingly keywords were not a thing in the RnRS until R7RS-large (partial support in R6RS).

Not sure about common lisp.