A mole (abbreviated as mol) is a unit for the amount of a substance. Specifically, 1 mole is equal to 6.02214076×1023 (also known as the Avogadro number) particles; these particles may be atoms, molecules, or ions.
Even though 1 mole of particles may sound like a lot of particles, in practice it is quite relevant to quantities you encounter in everyday life. For example, 1 mole of water has a mass of about 18 grams - which is approximately equivalent to the mass of 18 paperclips.
Although moles are correlated to measures of mass when discussing a single substance, it is important to note that moles are not a measure of mass or weight, as the conversion between moles and mass will depend on the identity (specifically, the molecular mass) of a substance.