Possible Clues:

• Prefix for 'night' or 'day'
• Lead-in to night or day
• Prefix with "night" or "flight"
• ''Central'' prefix for night
• Prefix meaning "central"
• Starter for stream
• Prefix with life or west
• It's central to what's covered up by brand imagery going all the way back
• Prefix for "western"
• Lead-in to sentence or section