Voiding, Surmounting With Another and Fimbriation
Any type of charge, but probably most often the ordinaries and subordinaries, can be "voided"; without further description, this means that a hole in the shape of the charge reveals the field behind it. Occasionally the hole is of a different tincture or shape (which must then be specified), so that the charge appears to be surcharged with a smaller charge.
Read more about this topic: Ordinary (heraldry)