Claim: The 12-hour clock divides the day into a.m. and p.m.
Evidence: The 12-hour clock is a time convention in which the 24 hours of the day are divided into two periods : a.m. -LRB- from the Latin , ante meridiem , meaning before midday -RRB- and p.m. -LRB- post meridiem , meaning past midday -RRB-.