Related Clues:

• Abbr. meaning 'We'll fill this slot in later'
• Letters on an incomplete syllabus
• Abbr. for an open slot
• Abbr. in an unfilled TV slot
• TV listing abbr
• As yet undecided, on a sched
• 'Ask me later,' initially
• “We don’t know yet,” briefly
• Schedule placeholder, for short
• TV itinerary abbr
• Scheduling letters
• 'Don't know yet' letters
• Still undetermined, on a sched
• 'Check back later' (Abbr.)
• Undecided, on a TV sched