The following is a word study from Dr. Ike Tennison.
According to various English translations of Paul’s remarks made in Greek in Galatians 1:18, Paul went to Jerusalem to “see” or “visit” or “get acquainted with” Peter. There are several Greek words for “see” or “visit” or “get acquainted with,” but the word used in this verse is not one of them. The word used here is what is called a hapax legomenon—which means “something said only once” and, in this case, that means the use of the word in Galatians 1:18 is the only place in the entire New Testament where it is used. What does this word mean?
The Greek word is transliterated historesai, the aorist active infinitive of the Greek contract verb historeo. Contract verbs are derived from nouns. In this case, the noun is histor or istor. In ancient Greece, when a decision needed to be made, the council of elders took turns addressing the issue. After all had spoken, the judge of which speech won (made the decision) was an istor. Therefore, the verb used by Paul is much stronger than simply “see” or “visit” or “get acquainted with.” Rather, the verb means something like “judge” in regard to Peter’s position on certain issues (undoubtedly, on the issue of circumcision for the Gentiles; see, e.g., Galatians 2:1-10). In this case, it probably means that Paul listened to Peter’s argument that the Gentiles had to obey the law in full and judged Peter’s words against his own understanding of the law in regard to the Gentiles.