Washington Post July 21 issue carries an article under the headline, “The Cruz-Trump relationship goes solid #TBT,” followed by the lead copy;
And now the finale. Tonight is "Making America One Again" night in Cleveland, featuring speeches by Reince Priebus, Ivanka Trump, and of course, the nominee himself.
Cambridge English Dictionary doesn’t carry the word, TBT. Oxford English Dictionary defines it as [chemical] an abbreviation of Tributyltin.
internetslang com. defines it as an internet slang for “Truth be told,” which reminded me of a corporate slogan of a New York-based ad agency I happend to work there for more than 30 years – “Truth well told.” I don't know if the company slogan I was familiar with is relevant to "#TBT,” or not.
Is “(#)TBT” a common English term? How can I interpret, and translate “The Cruz-Trump relationship goes solid #TBT” in plain English?