H/T refers to a popular Twitter acronym, used for abbreviating the phrase “Hat Tip” which is a form of respect online.
It is unclear, how long “H/T” has exactly been around, although the phrase of hat tipping as a form of respect can be traced back into the 1960’s, associated with Jimmy Hatlo, whose hat must have tipped lo.
“H/T” in its current form first appeared not long after the launch of Twitter in 2006.
The acronym was first defined on Urban Dictionary in 2008.
With the rising prominence of Twitter in the 2010’s, “H/T” became a common form of giving respect or paying homage to one another on the internet.