I've noticed lately that some automobile companies refer to a sunroof and some refer to a moonroof. After car shopping myself yesterday, I ran across this again, and of course, had to look it up. One thing I learned, there is literally a website for everything. Seriously, in another window right now I have sunroofs.org open! Can you believe it! There's a need for sunroofs.org. So what is the difference betwen a sunroof and a moonroof. Today, nada. I verified this on several websites. Moonroof is a term introduced by good 'ol Henry Ford in the 70's. Taken from sunroof.org (wow, three plugs here!): Sunroof is the generic term used to describe an operable panel in a vehicle roof which can let in light and/or air. Moonroof is a term created by Ford in the 70's, yet is now used generically to describe glass panel inbuilt electric sunroofs.
As a second source, here's Wikipedia's answer, abridged of course: Historically, European factory installed sunroofs have been opaque, and slide open to allow sunshine and fresh air into the passenger compartment. Most factory sunroofs offered today feature a glass panel, and are often referred to as moonroofs, a term introduced by Ford in the 1970s.
Variations have become the norm in both factory installed and aftermarket offerings, creating a wide range of features and choices.