Source : Free On-Line Dictionary of Computing

aggregate type
     
         A data {type} composed of multiple elements.  An
        aggregate can be homogeneous (all elements have the same type)
        e.g. an {array}, a list in a {functional language}, a string
        of characters, a file; or it can be heterogeneous (elements
        can have different types) e.g. a {structure}.  In most
        languages aggregates can contain elements which are themselves
        aggregates. e.g. a list of lists.
     
        See also {union}.
     
        (1996-03-23)