Related Clues:

• Fluorescent tube gas
• It lights up the night
• About 1% of the Earth's atmosphere
• Glower
• Like highlighter colors
• Fluorescent
• Times Square light
• Sign filler
• Liquid ___ (refrigerant)
• Light fill
• Light on Broadway
• Marquee material, perhaps
• Quite bright
• Element no. 10
• Night light?