1) The first price of the day for a contract on a securities or futures exchange. Futures exchanges post opening ranges for daily trading. Due to the fast-moving operation of futures markets, this range of closely related prices allows market participants to fill contracts at any price within the range, rather than be restricted to one price. The daily prices that are published are approximate medians of the opening range; 2) When markets are in session, or contracts are being traded, the markets are said to be "open."
OPEN
Meaning of OPEN in English
A guide to futures and options market technology English dictionary. Английский словарь-руководство по фьючерсам и опционам рыночных технологий . 2012