source
/ˈsoɚs/
noun
sourcenoun
/ˈsoɚs/источник
the place, thing, or person that something comes from
  • The newspaper did not reveal the source of the information.
  • Rivers often begin at a small source high in the mountains.
From the textIn 1786 he wrote that Sanskrit, Greek, and Latin all came from a 'common source', which had perhaps disappeared.