>>14One of the very first lessons of the wizard book is that data is a type of abstract being that inhabits the computer (programs are another). Indeed programs are a kind of data which is executable by some other program. An executing program is called a process.
A Lisp program is a collection of Lisp objects, which are data. Sometimes a Lisp program is called "Lisp code".
The syntax (or structure) of a Lisp program is defined in terms of Lisp objects.
Text can be read by some program (possibly a Lisp program) which generates Lisp objects during the time it is reading that text. Conventionally, a program that reads text and generates Lisp objects is called a Lisp reader.
Lisp objects that are read in by a Lisp reader may also be Lisp programs.
One family of textual syntaxes Lisp readers usually understand are called "S-expressions". However there are others e.g. "M-expressions", "Sweet expressions" etc.
I hope this answers your questions.