A substance made up of atoms with the same atomic number; common examples are hydrogen, gold, and iron.
any of the more than 100 known substances (of which 93 occur naturally) that cannot be separated into simpler substances and that singly or in combination constitute all matter
any of the more than 100 known substances (of which 92 occur naturally) that cannot be separated into simpler substances and that singly or in combination constitute all matter
