source noun \ˈsȯrs\

: someone or something that provides what is wanted or needed

: the cause of something (such as a happiness)

: a person, book, etc, that gives information

Full Definition of SOURCE

1a :  a generative force :  cause
  b (1) :  a point of origin of procurement :  beginning
     (2) :  one that initiates :  author; also :  prototype, model
     (3) :  one that supplies information

2a :  the point of origin of a stream of water :  fountainheadb archaic :  spring, fount

3:  a firsthand document or primary reference work