Column without a label
An array is a temporary grouping of SAS variables that are arranged in a particular order and identified by an array-name. The array exists only for the duration of the current DATA step. The array-name distinguishes it from any other arrays in the same DATA step; it is not a variable.
A multidimensional array is a more complex grouping of variables that, when processed, results in output that could have two or more dimensions, such as columns and rows.
A SAS data library is a collection of one or more SAS files that are recognized by SAS and that are referenced and stored as a unit. Each file is a member of the library. The logical concept of a SAS data library remains constant, regardless of the operating environment. In any operating environment where SAS can be installed, the structure for organizing,locating, and managing SAS files is the same. At the operating environment level,however, a SAS data library has different physical implementations. Most SAS data libraries implement the storage of files in a manner similar to the way the operating environment stores and accesses files. For instance, in directory-based operating environments, a SAS data library is a group of SAS files that are stored in the same directory and accessed by the same engine. Other files can be stored in the directory, but only the files with file extensions that are assigned by SAS are recognized as part of the SAS data library.