The process by which a jury is chosen for trial from among a group of eligible people by questioning them on their ability and willingness to be fair and impartial and decide the case based only on the evidence presented at trial.
Merriam-Webster Online Dictionary
voir dire (noun)
a preliminary examination to determine the competency of a witness or juror
For criminal defendants, the right to a jury trial is found in the Sixth Amendment of the U.S. Constitution. This right and the others enshrined in the Constitution are intended to keep the country from instituting an oppressive government.
Arizona has a similar right to a trial by jury found in Ariz. Const. Art. VI § 17. The right to a jury trial in criminal cases is recognized in felony cases in Arizona.