TOP / UNDERMOUNT
The edges of a top mount sink sit on the countertop, the most common type. This method is practical, easy to install & very lasting.
Some sinks are of the undermount type, the edge is sandwiched between the countertop & the cabinet carcass to achieve a sleek look. It more commonly associated with designer kitchens. The installation is more difficult & overtime the failure of the sealant may result in moisture seeping into the cabinet to cause damage.