It stands for Double Tap on Instagram. Meaning they want you to like the photo by double tapping/clicking on it.
dt means online dating and fbm means facebook meet
Design Technology
Down town
If by DT you mean Design and Technology then the answer is: La technologie (you also need some accents)
deep throat specialist
While some people refers it to InstaGram. The most common acronym for InStaGram is "Insta" or "ISG".
Digital Television
IT means computer-aided manufacturer!
to study something u get me fam
DT stands for Dip Tube and the number is the length from the OPD valve. Source www.protanksupply.com
J
On Instagram, if you are mentioned, it means the other person has tagged you to include you in their conversation.