Cross
As relates to Christianity, it is the instrument of crucifixion. It is a single vertical stake with a cross member near or at the top by which a person is either nailed and/or tied with outstretched arms. Jesus was nailed on a cross, not a stake since in John 20:25, Thomas stated that he would not believe that Jesus had risen from the dead unless he saw "...in His hands the imprint of the nails..." A cross would require at least two nails, one for each outstretched hand.