What is the difference between guide words and entry words?

Look in any dictionary (book, not online!)

At the top of each page is a guide Word - usually the first or last entry on the page.

In the dictionary are Words printed in alphabetical order. Each of these entries is an entry Word.

You could have found this out by googling or looking up in a dictionary :

Entry Word - Noun, entry Word - the form of a Word that heads a lexical entry and is alphabetized in a dictionary. citation form, main entry Word

Guide Word - Word printed at the top of a page in a dictionary, encyclopedia, etc., usually the first or last entry on the page