A "level lock" is a game mechanic that prevents players outside of a certain level range from entering an area.
Maxlock— A "max lock" prevents players over a specific level from entering. Thus, if an area is "maxlock 30", anyone over level 30 may not enter.
Minlock— A "min lock" prevents players under a specific level from entering. Thus if an area is "minlock 50", anyone under level 50 may not enter.
Currently, all maxlocks of level 45 and higher have been canceled. However, the lock DOES exist, which has created an issue where a pet can be summoned by a player over the lock, but will not follow the player into other rooms in the area.