Breast augmentation: Enlargement of the breasts. Augmentation of the breast typically consists of insertion of a silicone bag (prosthesis) under the breast (submammary) or under the breast and chest muscle (subpectoral) and then filling the bag with saline (salt water). This prosthesis expands the breast area to give a fuller breast (increased cup size), give a better contour, and give more cleavage.

Also known as breast implant.