From pentēkonta (fifty) and etos (year). Fifty years old. Used in Acts 13:20 in connection with the period of the judges.
In Acts 13:20, Paul recounts that God gave Israel judges for about four hundred and fifty years. The number fifty also connects to the Year of Jubilee — every fiftieth year, debts were canceled, slaves freed, and land returned. Jesus' ministry inaugurated the ultimate Jubilee: freedom from the debt of sin, liberation from spiritual slavery, and restoration of humanity's lost inheritance.