R.C. Sproul Jr. offers some helpful theological definitions for different eschatological positions. His definition of postmillennial eschatology is quite helpful:
…and the second most common view among the Reformed would be the postmillennial view. This view holds that Jesus will return after a golden age on earth (some seeing this golden age being an indefinite period of time, others seeing it as a literal thousand years). It affirms that the calling of the church, as the bride of Christ, is to be about the business of Eve with respect to Adam. That is, the first Adam was called to subdue the earth, and Eve was to serve as a help suitable for that work. The second Adam is now fulfilling that calling, bringing all things under subjection, and the second Eve, the church is to serve as a help suitable for that work.