It means that most or all the church fathers, who dealt with the subject, are in agreement as to what it means. There must be at least five church fathers who have dealt with the issue in order to get any kind of consensus. The Principle of Probability Illumination, interpretation, and confirmation is the correct order. Illumination is the Spirit's unveiling the meaning of the text to the believer. In this one has what might be called a subjective confirmation of the meaning of the Scriptures.
Interpretation is the process of applying the rules of interpretation to a passage of Scripture.
In so far as the interpretation follows these rules, it is correct. By discovering that an interpretation faithfully follows these rules, one has objective confirmation as to the meaning of that passage. Finally, the last step is to confirm the interpretation by an examination of the consensus of the church fathers. The reason interpretation comes before confirmation is that it is always possible, however unlikely, that the church fathers are wrong. We can thank God that He gave us an objective means of confirming the interpretation of Scripture.