OK, I think it really is Hard Disk Drive. This is cut & pasted from a Toyota.com blurb about the Land Cruiser (bold added by me):
"For the 2013 model year, Land Cruiser receives exterior and interior styling enhancements. Additionally, Land Cruiser will now come with all features as standard equipment, including new driving performance features, and an array of significant safety and convenience features. Among the many popular features that were formerly available as options, but are now standard, are rear-seat DVD entertainment system, color-keyed rear spoiler, rain-sensing windshield wipers, center-console cooler box, headlamp cleaners, leather-trimmed steering wheel, multi-information display, voice and Bluetooth® hands-free controls, leather-trimmed shift lever and heated second row seats. Toyota’s Premium Hard Disk Drive (HDD) Navigation with Entune multi-media system and JBL® audio is also standard."
Robert N.