Related Clues:

• Element of an element
• Science word from the Greek for 'indivisible'
• Science word from the Greek for "indivisible"
• A cat bit
• One tiny bit
• Small unit of matter studied by Lise Meitner
• Subatomic particle (Higgs, perhaps)
• Tiny particle that's a building block
• If an apple were magnified to the size of the Earth, this would be close to the size of an apple
• Molecule particle
• Chemistry unit whose size is measured in angstroms
• Model in a science classroom
• Small thing
• Subject of Niels Bohr's model
• Very small bit of a 15?