level

level

(lev' ul) n.

1. a vertical location, rank, position in a hierarchy, etc.

2. one of several separate words that make up the name of a file, variable, etc. (connected by periods), or the relative position occupied by the word in the name.

MAIN is the first level of the name MAIN.PROJECT.
The fourth level of an entry name is the entry type.

3. Proc step. a distinct value of class variables, or the set of observations having that value.

4. a degree of indirectness in the references required to identify or reach an object: %INCLUDE (level 2).