ATTN is an abbreviation for the word attention.
It is mostly encountered in digital communication, be it text messages or elsewhere on the internet.
“ATTN” like many other internet abbreviations was first conceived in the mid-1990’s, when the web became more accessible to the masses.
Its first cases would emerge on forums and message boards, as well as e-mails.
“ATTN” was first defined on Urban Dictionary in 2003, with a few other entries having been uploaded since that time.
The emergence of SMS technology in the 2000’s as well as social media in the 2010’s all helped solidify the frequency of the abbreviation.