(ecology) A particular position occupied by a group of organisms in a food chain.

Any of several internationally agreed standard altitudes that are based on atmospheric pressure rather than on true height

The property of being level-headed.

(economics) An index of the average market price of selected goods weighted according to certain criteria.

The relative difficulty of completing a task or objective. / (video games) A variable setting in a video game determining how challenging it is to play.

(statistics) A measure of how likely it is to draw a false conclusion in a statistical test, when the results are really just random variations.

A tool employing a chamber with a colored liquid and an air bubble, used to determine if a surface is level horizontally, vertically, or at a 45-degree angle.

plural of trophic level

A subject-based qualification superseded in England by GCSEs, but still available as an international examination.

Alternative spelling of O-level