What does "d-" in decimal number mean

Question

I'm trying to implement some functions over Amazon's Ion Value, while reading its document, I found an example of decimal number is 6.62607015d-34 what does d- mean here? Thanks

Answer 1

Do you know the notation 1.234e-56 for $1.234\times 10^{-56}$? Obviously, 1.234d-56 means the same but creates a value of type decimal instead of float.