Added to the Merriam-Webster
dictionary incorrectly, its original definition is:
1. D or d (n): Abbreviation for "Density".
This was however entered incorrectly as "Dord", giving it this definition.
If you wanted to use it in the context of an adjective, it can
mean...
2. Dord (adj): Alternate word for "Dense".
Due to this mistake it can however take on another meaning.
3. Dord (n): A word that is incorrectly used or does not technically exist either through intention or misconception.
"Dord" itself falls into this description, and so does pretty much everything else on Urban
Dictionary.
This can be imagined as an abbreviation for "Denied word", as a mnemonic device though that is not its origin.