December (Roman month) December (Roman month) December (from Latin "decem", "ten") or mensis December was originally the tenth month of the Roman calendar, following November ("novem", "nine") and preceding Ianuarius. It had 29 days. When the calendar was reformed to create a 12-month year starting in Ianuarius, December became the twelfth month, but retained its name, as did the other numbered months from Quintilis (July) through December. Its length was increased to 31 days under the Julian calendar reform. The Romans did not number days of a month sequentially from the first day through the last. Instead, they counted back from the three
Delivery month futures exchanges (such as bonds, short-term interest rates, foreign exchange and US stock indexes) tend to expire quarterly, in March, June, September and December. For financial contracts traded on non-US futures exchanges, the expiration schedule may not be quarterly. This table lists the conventional letter codes used in tickers to specify delivery month: To name a specific contract in a financial futures market, the month code will follow the contract code, and in turn be followed by the year. For example, CLZ3 is the December 2023 NYMEX crude oil contract. CL denotes crude oil (crude light), Z corresponds to the