King James Bible (Cambridge Ed.)<quoted text>
Yes BC means before Christ.
AD is Latin for the year of our Lord.
As for 1day = 1000 years that is not for Geneses.
2 Peter 3:8
But, beloved, be not ignorant of this one thing, that one day is with the Lord as a thousand years, and a thousand years as one day.
Psalm 90:4 A thousand years in your sight are like a day that has just gone by, or like a watch in the night.