This is the verse translation, not a definition of the individual word.
Say [O believers], “We believe in Allah and what has been sent down to us; and what was sent down to Abraham, Ishmael, Isaac, Jacob, and the descendants [of Jacob][1]; and what was given to Moses and Jesus; and what was given to the prophets from their Lord. We make no distinction between any of them, and to Him we have submitted.”
Source
[1] i.e., the twelve tribes of Israel descended from Jacob.