`

` is a Lisp macro in `backquote.el'.

(\` STRUCTURE)

Argument STRUCTURE describes a template to build.

The whole structure acts as if it were quoted except for certain
places where expressions are evaluated and inserted or spliced in.

For example:

b => (ba bb bc) ; assume b has this value
`(a b c) => (a b c) ; backquote acts like quote
`(a ,b c) => (a (ba bb bc) c) ; insert the value of b
`(a ,@b c) => (a ba bb bc c) ; splice in the value of b

Vectors work just like lists. Nested backquotes are permitted.