Ph.D is a term used in the Anglophone world as shorthand for Philosopiae doctor, or doctor in philosophy.
The term Philosophy comes from the Latin word “philosophĭa”, which is derived from the Greek word ϕιλoσoϕία, whose roots are φιλεῖν (phileîn- to love) and «σoϕία» (sophia-knowledge).
So the first and most ethanol ogi al correct meaning of philosopher is “knowledge lover”. Definitely someone who shouldn’t need to lookup in a dictionary how to spell his title.
Nullius illum miseret, si scribere 'Philosophiæ’ non scit