Enterprise was the name of the hard drive (like Caviar, Protegé, Scorpio, etc), used only for WD's short-lived SCSI devices. The majority of the Enterprise drives were 7200 RPM, though some 5400 or 10k RPM models may exist. They were quite expensive with relatively lack-lustre performance and consequently didn't sell all that well, so WD killed off that endeavor when they started losing excessive amounts of money in the late 90s. I don't think anybody cried about it.

I once found a 50-pin Enterprise and tried using it in a Mac. It never worked. I could never figure out why. Maybe it just didn't like the Mac's SCSI setup or something, because it would work in peecees. I dunno. It was only a 2GB or something, so I really didn't bother to pursue the issue.