If your arrays start at 0, you have offsets. If your arrays start at 1, you have indexes. "0-indexed" shouldn't be a thing. I like the screenshot quote that

If your arrays start at 0, you have offsets. If your arrays start at 1, you have indexes. "0-indexed" shouldn't be a thing. I like the screenshot quote that refers to this as either "1-origin" or "0-origin".