the number four; complex form used for financial purposes is 肆 sì

the chemical element hydrogen, a colorless, odorless, and tasteless gas that is the lightest of all known substances; usually referred to as 氢气 qīng​qì

marijuana; cannabis; a drug made from the female hemp plant that affects the mind and body

A type of organic compound where a hydroxyl group is linked directly to a carbon atom in a benzene ring; specifically refers to carbolic acid or its derivatives.