"delta" refers to the difference or change between two things. It can be used to describe the variation or amount by which something has transformed over time. Full definition
If the same product is available on Delta SkyMiles with miles to earn, it will pop up a reminder. (lendedu.com)
Award redemptions to the northern South America region cost quite a bit on flagship carriers: 35,000 AAdvantage miles (round - trip ticket on American Airlines), 40,000 MileagePlus miles on United Airlines, and 45,000 SkyMiles on Delta Air Lines... and these are at the lowest award levels in economy class. (upgradedpoints.com)
Although it cost me a ridiculous 85,000 SkyMiles, I was okay with that since I found it very easy to accumulate a lot of Delta SkyMiles in a short times with credit card offers out there for 60K and 70K. (uponarriving.com)