In context of general equities, market order or limited price order that is to be executed at the opening (and corresponding price) of the stock or not at all, and any such order or portion thereof not so executed is to be treated as cancelled .
AT THE OPENING ORDER
Meaning of AT THE OPENING ORDER in English
Campbell R. Harvey. Hypertextual finance English glossary. Английский словарь гипертекстовых финансов. 2012