Short for LISt Processing.
A modern dialect is Scheme--although that identification is about as incendiary in some circles as the observation that political, not linguistic, markers separate Serbia from Croatia.
See Tcl and LISP or Playing LISP.
Good LISP reading: http://www.paulgraham.com/onlisptext.html , http://www.norvig.com/paip.html .
On Tcl: "No question but that real lisps are more powerful than this bastard child of lisp and awk, but for what it does it does a better job than either parent. Which is all you need to ask of it." (Peter da Silva, 1994 [L1 ])
How close is the correspondence?
... maps closely to ( ... )
{ ... } seems to be '( ... )
The difference (apart from expr, of course) is more in how words are grouped - in Lisp they form a list of tokens, not a string. So manipulating expressions "as text" is done by manipulating tokens in macros. And I'm at a bit of a loss to explain $...