Unders and partials are the same thing, no Drs do FULL unders any more, so partials are often referred to as UNDERS. Unders/partials are where the top part of the implant is placed under the muscle and breast tissue and the bottom half is left over the muscle behind the breast tissue.
Overs is where the implant is placed on top of the muscle, just behind the breast tissue,
Full/true unders is where everything is placed under the muscle but like I mentioned above this isn;t really done anymore.
Hope this helps.
