I don't know.
What’s The Difference Between Acronyms And Abbreviations?Is there a difference between acronyms and abbreviations? Most people think they’re pretty similar … and they’re definitely used in similar ways. But, there are slight differences What is an abbreviation? An abbreviation is any shortened or contracted form of a word or phrase. Did you catch the word any in there? That means abbreviation is the blanket term for all these shortened words we’ve all been using …
Origin of IDK
from its use in digital communications
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019