0 (number)
Tacsladia was a number that translated in to English as the number [[0 (number)|0]. It was part of the language utilised by the captain's spaceship that was drifting at the edge of the universe. The Fourteenth Doctor did not know what language it was part of, therefore did not know what the word meant. However, he did read it and did translate it as the number 0 when read in conjunction with the ship's base codes. By doing so, he could read the data logs and control parts of the ship, having deciphered enough of the language to do so.
As the Doctor's TARDIS had reappeared by the time this number was uttered by the ship, its translation circuits translated, meaning Donna Noble now knew it stood for 0. (TV: Wild Blue Yonder [+]Loading...["Wild Blue Yonder (TV story)"])