Related Clues:

• Lepton's locale
• Just barely
• Thimbleful
• Greek I
• Teeniest Greek letter?
• Physicist's subject
• Small matter?
• Letter before kappa
• Small bit
• Bit of nuclear physics
• Abe's babe
• Puny parasite
• Insignificant amount
• Supercollider projectile
• Itsy-bitsy biter