Is HKD based on USD?

Could you please clarify for me if the Hong Kong Dollar (HKD) is actually based on the United States Dollar (USD)? I've heard that the Hong Kong Monetary Authority maintains a linked exchange rate system where the HKD is pegged to the USD, but I'm not entirely sure if that means it's based on the USD in the same way that other currencies are. Could you provide some insight into how the HKD's value is determined relative to the USD and whether or not it can be considered a currency that is fundamentally based on the USD?