jury of one's peers

Definition from Nolo’s Plain-English Law Dictionary

The constitutionally guaranteed right of criminal defendants to be tried by their equals, that is, by an impartial group of citizens from the legal jurisdiction where they live. This has been interpreted by courts to mean that the jurors should include a broad representation of the population, particularly with regard to race, national origin, and gender. Notice that this doesn't mean that, for example, women are to be tried by women, Asians by Asians, or African Americans by African Americans. When selecting a jury, the lawyers may not exclude people of a particular race or intentionally narrow the spectrum of possible jurors.

Definition provided by Nolo’s Plain-English Law Dictionary.