Bc

An abbreviation used to denote so many years "Before Christ" or before the beginning of the Christian calendar. The lowercase 'bc' represents uncalibrated radiocarbon years; the capitals BC denote a calibrated radiocarbon date or a date such as an historically derived one that does not need calibration. There is no year 0: 1 BC is the same year as AD 1 or 1 AD.

Be. Years before Christ. The lower case ‘be’ represents uncalibrated radiocarbon years; the capitals BC denote a calibrated radiocarbon date, or a date such as an historically derived one, that does not need calibration (see Table 8, p. 422). There is no year 0: 1 bc is the same year as ad 1.