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 is implementation-dependent.