High Low Open Close

From Reuters Financial Glossary

Synonym: HLOC

These represent the four most important types of price information which are displayed in most price displays and charts. High is the highest level at which a security or commodity has traded, while low is the lowest level. Depending on the instrument, it can be the high/low that day, month, year, or since price records began. Open/close are the opening and closing levels for any of those periods.