Breast augmentation and augmentation mammoplasty (colloquially known as a "boob job") are plastic surgery terms for the breast-implant and the fat-graft mammoplasty approaches used to increase the size, change the shape, and alter the texture of the breasts of a woman. As a primary reconstruction, augmentation mammoplasty is applied to effect a post–mastectomy breast reconstruction, the repair of the chest wound consequent to the removal of a cancerous breast; to correct congenital defects of the breast(s); and to correct congenital defects of the chest wall. As an elective, cosmetic surgery, primary augmentation changes the aesthetics — of size, shape, and texture — of healthy breasts. The surgical implantation approach effects the global augmentation of the breast hemisphere using a breast implant, either an implant filled with saline-solution, or an implant filled with silicone-gel; moreover, the surgical augmentation approach can include the application of transplanted autologous skin flaps harvested from the woman’s body. The fat-graft transfer approach augments the size and corrects contour defects of the breast hemisphere with grafts of autologous adipocyte fat tissue, drawn from the woman’s body.

A breast implant is a prosthesis used to change the size, shape, and contour of a woman’s breast. In reconstructive plastic surgery, breast implants can be placed to restore a natural looking breast mound for post–mastectomy breast reconstruction patients or to correct congenital defects and deformities of the chest wall. They are also used cosmetically to enhance or enlarge the appearance of the breast through breast augmentation surgery.