I cringe at having to be pedantic and quote specific events, but in The Deadly Assassin, the Castellan clearly states after it being called a type 40 capsule that "this is a TARDIS". It's around 2.45 into the first episode. There are no companions present and unless it's being translated through the TARDIS telepathic circuits for the viewers and 'breaking the fourth wall' I have to acknowledge that a time capsule is known as a 'TARDIS' on Gallifrey.
I didn't recall this moment. Fair enough, I can be wrong.
"We can go anywhere and any time in the universe. But it will probably be London during the Blitz." -Inspector Spacetime