pro marks a person, event, or time as earlier than, ahead of, or in front of a stated reference point.

As a preposition, it marks a relation of precedence: an event may occur earlier than another event, a person may be ahead of someone else, or something may stand in front of a place or person.

1. Preposition marking precedence or position ahead · dominant

   The supplied morphology identifies it as a preposition throughout. In John 13:19 the APB renders the clause "before it happens," locating the telling earlier than the event; in Luke 9:52 it renders messengers sent "before his face," and in Acts 12:6 guards keeping watch "before the door of the prison," showing precedence or position relative to a person or place.

   John 13:19Luke 9:52Acts 12:61 Corinthians 4:5John 5:72 Timothy 4:21

In the Anselm Project Bible: The APB commonly presents the relation with "before," including temporal clauses such as John 13:19 and positional clauses such as Acts 12:6; it also uses "ahead" in Luke 10:1. These renderings indicate the clauses' overall relations rather than a fixed English equivalent.