King James Bible Dictionary

a stake or post (as set upright) that is (specifically) a pole or cross (as an instrument of capital punishment); figuratively exposure to death that is self denial; by implication the atonement of Christ

1. an upright stake, esp. a pointed one

2. a cross

a. a well known instrument of most cruel and ignominious punishment, borrowed by the Greeks and Romans from the Phoenicians; to it were affixed among the Romans, down to the time of Constantine the Great, the guiltiest criminals, particularly the basest slaves, robbers, the authors and abetters of insurrections, and occasionally in the provinces, at the arbitrary pleasure of the governors, upright and peaceable men also, and even Roman citizens themselves

b. the crucifixion which Christ underwent