An overseer, one who has the charge and direction of any thing. The most common acceptation of the word in the New Testament, is that which occurs Acts 20:28 Philippians 1:1, where it signifies Christ "the Shepherd and Bishop of your souls," 1 Peter 2:25. Paul describes the qualities requisite in bishops, 1 Timothy 3:2 Titus 1:7, etc.; Christ himself is their great exemplar.
These dictionary topics are from American Tract Society Bible Dictionary published in 1859. Public Domain, copy freely.
Rand, W. W. "Entry for 'BISHOP'". "American Tract Society Bible Dictionary".