The term full bar means that the first finger bars across all six strings. When the full bar is used, the chord itself is called a bar chord. The fact that there are no open strings in a bar chord means it is possible to move the one shape to all positions of the fretboard and play in every key. The following diagrams are two common bar chords–F which uses a full bar at the first fret, and B minor which uses a full bar at the second fret. Practice changing between them as shown in the next example.
F
Bm