Related Clues:

• Kind of reactor
• Very tiny
• Like some energy
• Type of clock or number
• Type of energy
• Like some precise clocks
• The first letter in 84-Across
• __ reactor
• Wing adjective
• Word with age or weight
• Very, very tiny
• Word with particle or pile
• Word before number or weight
• Teeny-tiny
• Part of 106 Across