It wouldn't be, because ð is an eth, not a delta (δ). Eth is an old english letter.

Or a current icelandic letter.

What are you going for here? e, a, and k are all English rather than Greek letters. It's just a transcription for the benefit of people who aren't comfortable with Greek letter names.

Even then, wouldn't a delta just be a "d"? Or do Greeks pronounce the "th" in "the"?