Related Clues:

• Allow only one to a customer
• Keep under
• Put a top on
• Line in the sand, say
• It may hold your horses
• Jock strap?
• Terminal point
• Equestrian's control
• Word after speed or term
• Stage lead?
• Line from a hack
• As high as you can possibly go
• Control device
• Draw a line
• Put in a straitjacket, e.g.