Possible Clues:

• Limit a large town’s dimensions
• Size of area in top conurbation
• Limit set by a developed place for what a ground can hold
• Power (to do something); volume
• Containable amount
• Volume better to the west of a large town
• Skill seen in Crown Derby for example
• Space; ability
• Better, a civic role
• Size limit put on one place where many live