I'm looking for a Latin phrase for starting your exposition by explaining the terms, i.e. its title. I believe the quote is "initium doctrinae sit consideratio nominis," but I'm not sure that that's correct. I haven't been able to find it online, so I'd also like a reference to it in use.
As Joel Derfner points out, the quote comes from the Stoic philosopher Epictetus, and is originally in Greek; it can be found here, in a collection of his sayings by his student Arrian, in the form ἀρχὴ παιδεύσεως ἡ τῶν ὀνομάτων ἐπίσκεψις. In that text the quote seems to be ascribed by Epictetus to the fifth- and fourth-century BC philosopher Antisthenes, a student of Socrates.
The earliest Latin version I can find is from 1604, in Justus Lipsius's Manuductio ad Stoicam Philosophiam. The Latin translation -- initium disciplinae nominum consideratio -- is presumably Lipsius's own, unless there's an earlier Latin version I've missed.
So actually your translation isn't correct—or, rather, it's technically correct, but it's not actually correct. I'll explain.
(I should note that this is an edited version of my previous answer—the edits are based on @TKR's comments to this answer.)
The sentence you quote the Latin version of a sentence from the Discourses of the Stoic philosopher Epictetus. The Discourses are transcripts of his lectures, written not by him but by his student Arrian, who wrote in Greek rather than in Latin. Epictetus, however, attributes the sentence to Antisthenes. The sentence means, more or less, "The beginning of education is the consideration [or "the study"] of names."