Mole

The amount of a substance that contains exactly 6.02214076 × 10²³ particles.

Example:
• 1 mole of hydrogen atoms has a mass of about 1.008 grams
• 1 mole of carbon-12 atoms has a mass of 12 grams (the original definition)

We can have moles of atoms, molecules, protons and more.

October 23 is Mole Day (because of 10²³).