There are a couple of symbols the emacs‘ lisp interpreter gives special meaning to. Since for some reason these never made it into my long-term memory I collect them here for later reference. Quotes are copied from all over the internet. Reference to the source is given in the last column.
|#||The sharp quote (or function quote, or simply #‘) is an abbreviation for the function form. It is essentially a version of quote (or ‚) which enables byte-compilation, but its actual usefulness has changed throughout the years.||reference|
|`||Backquote constructs allow you to quote a list, but selectively evaluate elements of that list.||reference|
|:||A symbol whose name starts with a colon (‘:’) is called a keyword symbol. These symbols automatically act as constants, and are normally used only by comparing an unknown symbol with a few specific alternatives.||reference|
|,||Unquotes expressions in backquote-constructs.||reference|
|'||Prevents its single argument from beeing evaluated||reference|
|?||Introduces a „character literal“ (eg ?a). Evaluates to the printed representation of the character.||reference|