As for the word "philosopher" (etymologically, a lover of wisdom), a certain somewhat unreliable tradition traces it back to Pythagoras (about 582-500 B.C.).

As told by Cicero, the story is that, in a conversation with Leon, the ruler of Phlius, in the Peloponnesus, he described himself as a philosopher, and said that his business was an investigation into the nature of things.
At any rate, both the words "philosopher" and "philosophy" are freely used in the writings of the disciples of Socrates (470-399 B.C.), and it is possible that he was the first to make use of them.

The seeming modesty of the title philosopher--for etymologically it is a modest one, though it has managed to gather a very different signification with the lapse of time--the modesty of the title would naturally appeal to a man who claimed so much ignorance, as Socrates; and Plato represents him as distinguishing between the lover of wisdom and the wise, on the ground that God alone may be called wise.

From that date to this the word "philosopher" has remained with us, and it has meant many things to many men.

But for centuries the philosopher has not been simply the investigator, nor has he been simply the lover of wisdom.
An investigation into the origin of words, however interesting in itself, can tell us little of the uses to which words are put after they have come into being.