Addiction: Central nervous system (CNS) stimulants are addictive, even if they are not abused. Many factors, including the patient's personal history, the type of stimulant that is being taken, the dose of the drug, and duration of use, influence how likely an individual is to become addicted.
The source of all waves - mechanical or electromagnetic - is something that is vibrating. Matthew Donovan.
that from which something comes into existence, develops, or derives: the sun is our source of energy; the source of a difficulty; any person, place, or thing by which something is supplied: a source of pleasure; a person, book, document, etc. that provides information: to consult various sources