ANSI Common Lisp 24 System Construction 24.1 System Construction Concepts
To load a file is to treat its contents as code
and execute that code.
The file may contain source code or compiled code.
A file containing source code is called a source file.
Loading a source file is accomplished essentially
by sequentially reading2 the forms in the file,
evaluating each immediately after it is read.
A file containing compiled code is called a compiled file.
Loading a compiled file is similar to loading a source file,
except that the file does not contain text but rather an
implementation-dependent representation of pre-digested expressions
created by the compiler. Often, a compiled file can be loaded
more quickly than a source file.
See Section 3.2 Compilation.
The way in which a source file is distinguished from a compiled file