Possible Clues:

• Control, in a way
• End, as of one's patience
• Frontier this writer's established in literature
• What a parent may impose on screen time
• Restrict or confine
• Dave Pirner "There's a ___ to how long I can wait"
• Set boundaries
• "Take It to the ___"
• In speech, portray that object as restriction
• Drunk, one's within it? On the contrary