Where grooms presumably take their brides. Once the marriage ceremony is completed, the groom will inevitably take his wife to their permanent residence (save a few circumstances). It is tradition in many cultures (American and Western European for sure) for the couple to not simply walk through the doorway of their abode. Instead, the groom picks up his bride (in cradle fashion), and carries her through the doorway, or "through the threshold." This act is most often considered romantic, and a big ol' kiss often follows the carrying.