Re: How Big is the Eye of Harmony? (spoilers Journey to the center TAR
we saw them referred to by Gallifreyans as "TT capsules" in a couple of stories, but there were other references to "TARDIS" as a generic name before then, like mentions of "the Master's TARDIS." And then there was "The War Games," where the War Chief supplied knockoff time machines called SIDRATs, TARDIS spelled backward.
And to complicate it still further, the way Spandrell and Goth use the word in Deadly Assassin makes it sound as if TARDIS is a generally accepted term on Gallifrey, but only for the Type 40.
"Some days are better than others. They say that where I come from."
"Loudly, I imagine, on the day you left."
(Blake's 7 - Rumours of Death)