The full form of ATTT is ain’t that the truth.
The acronym “ATTT” is used to represent the phrase “ain’t that the truth.” This phrase is used in conversation by someone to show that they completely agree with something that someone has previously said.

Origin of ATTT
There is no specific origin information regarding the phrase “ain’t that the truth” or the acronym “ATTT.” However, this English phrase has been a part of everyday language for some time. It began as the phrase “isn’t that the truth” and with slang over time changed to “ain’t that the truth.” When electronic communications became popular, many of the everyday phrases and sayings we use daily were shortened to abbreviations or acronyms like this one to make texting and typing quicker, easier, and more convenient.

Other Meanings
The acronym “ATTT” has no other slang meanings. However, the acronym is used for many businesses and organizations such as “Australian Trauma Team Training,” “Advanced Thermal Treatment Technologies,” “Association of Tourism Teachers and Trainers.” and “Advanced Technology Think Tank.”

Example Conversations
A text message conversation between two friends.

Friend 1: I thought my life would get easier after high school but my parents were right! My life has just gotten so much more difficult!
Friend 2: ATTT!