PASTOR (רֹעֶ֣ה ; ποιμήν, G4478, shepherd). This word, which has come to be one of the most common and preferred designations of Protestant clergymen, has very few occurrences in the Scriptures.
The OT, or Heb., uses the sing. form only once (Jer 17:16 KJV, ASV), and the pl. form seven times. It may mean to “tend a flock,” to “keep company with.” It is used in the pl. in the same book, Jeremiah, as the sing. (Jer 2:8; 3:15; 10:21; 12:10; 22:22; 23:1, 2). Jeremiah alone uses the word in the OT.
“Pastor” occurs only once in the NT (Eph 4:11) where the pl. of ποιμήν, G4478, is a classification of Christian workers with Christian teachers, “and some pastors and teachers.” Two other uses of the root word in varied tenses are ποίμαινε, “feed” (John 21:15) and ποιμάνατε “feed” or “be shepherds” (1 Pet 5:2).
International Standard Bible Encyclopedia (1915)