According to Kant,a proposition whose predicate concept is contained in its subject concept is analytic, and a proposition whose predicate concept is not contained in its subject concept but related, is synthetic. The term "related" seems a bit vague here - related in what way?
an example of an analytic proposition is: All bachelors are unmarried
an example of a synthetic proposition is: All bachelors are alone
But both subjects here refer to the meaning of "bachelor", and the so-called synthetic proposition can be deduced from the analytic one.
Hi McCoy - there's no such thing as purely analytic propositions (i.e. not based on experience) - all are synthetic to some extent (i.e. based on experience). Kant was a brainy guy, but in many ways also confused. If you have not read my little book "A short critique of Kant's unreason," I recommend it.
My main website is having tech problems right now, but you can read it here: http://tl-archive.net/6_reflect/6_Book_2/6_book_2.htm