Caption

A Caption is the text used to identify a field.

For Custom Fields the Caption setting is used if you want to have a label for the field that is different than the field name. If the caption is not set, then the field name will be used as the caption.

In the case of a Built-in Field the caption can only be changed on External Pages. 

If you want the Caption to appear above the field instead of to the left of the field, prefix the caption with a tilde (~).

If you are using a Title Bar – Multiple Columns Custom Field to define the number of columns, but don't want the actual Title Bar to appear, use a Hyphen (-) in the Caption field.