Robert McLister·General·December 21, 2008Y/Y (YOY) An abbreviation for “Year-over-year.” In other words, it means “compared to last year at this time.” Like news like this?Join our CMT Updates list and get the latest news as it happens. Unsubscribe anytime. SUBSCRIBE! Thank you for subscribing. One more step: Please confirm your subscription via the email sent to you.