Parent-child relationship

From EDRM

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 1 2 3 4 5 6 7 8 9

In any taxonomy, the superior category can be called a parent, and its subcategories can be called children. An email can be considered, for example, to be a parent of any of its attachments. Conversely, an attachment can be considered to be a child of the email to which it is attached.