Article (grammar)
Revealing his true form to Ursula Blake and Elton Pope, "Victor Kennedy" proclaimed "you've dabbled with aliens... now meet the genuine article!" (TV: Love & Monsters)
Definite article
Following his regeneration, the Fourth Doctor told Harry Sullivan that, whilst Sullivan was a doctor, he was "the Doctor. The definite article, you might say." (TV: Robot [+]Loading...["Robot (TV story)"]) Similarly, the Twelfth Doctor corrected a Mondasian Cyberman, adding that he was "The original, you might say.", and ironically faced the same assertion when he crossed paths with the First Doctor. (TV: Twice Upon a Time [+]Loading...["Twice Upon a Time (TV story)"])
The Meep's chosen pronoun was the definite article and so was always referred to as the Meep. Upon learning this, the Fourteenth Doctor admitted "I do that". (TV: The Star Beast [+]Loading...["The Star Beast (TV story)"])