What is the difference between a diamond and star rating for a hotel?

I usually hear about hotels getting a 4 star or 5 star rating. But I was looking at the website for a hotel that I will be staying at in a month and it said that they are a 4 diamond hotel. I was just curious as to what the difference was. Thanks!!!What is the difference between a diamond and star rating for a hotel?Different places have different rating systems, there's no global standard. AAA gives out diamonds, and stars are given by Michelin. Stars are also used to show the level of services available at a particular hotel. If, for example, the Four Seasons didn't offer their guests anything aside from a place to rest their heads, they'd probably only receive 1 star. But because they offer concierge services, restaurants, spas, in-room services and other "extras," their properties tend to receive high star ratings.