Movement rates represent the distance a character (or monster) can move in one minute (1 round). If a character is moving cautiously (e.g., stalking, mapping), this movement rate is divided by 10. A party of adventurers with a movement rate of 90-ft would move at 90-ft per turn through a dungeon (moving cautiously), and in combat (not moving cautiously) they would be moving 90-ft in a round. Running allows the character to double his or her movement rate. During combat, a flat-out run is not possible unless performing a charge or fleeing from combat.
Dividing movement rate by 5 (e.g., 60-ft becomes 12) gives the number of miles the character can travel in a day at walking speed along fairly level terrain. Thus, a character with a movement rate of 120-ft can march 24 miles in one day. Mounted characters use their horse's movement rate rather than their own, of course.