I've got an e-mail from Ken Tidwell about his use of the term ludology back in 1996 saying:

"As far as I know I made it up when I titled that page. Its derivation is wrong as 'ludo' is not Greek for game. Embarrassing, really, but languages are not my strong suit."

I must say in ludology we find a tradition for putting words together with different linguistic origins - e. g. Roger Caillois' game types using terms from both latin, greek and english. This mix of languages may turn out to be a ludologic trademark of playing with words.