Apron Front sinks are different from the standard sink style. Normally, the basin drops into a hole and is supported by the surrounding counter and the cabinet below. With an apron front mount, the basin pushes into the cabinet and is not supported by any counters. Sinks fully loaded with water and dishes can be very heavy. This is why it is very important to build extra supports underneath the sink. Apron mount sinks also tend to have deeper basins, this combined with the ""lip"" in front of the sink allows for more heavy duty usage.
Countertop sinks sit right on top of the cabinet and counter. It is esssentialy a sink bowl that is on top of the counter giving a more unique look to your kitchen or bathroom.
Drop-In sinks are standard. They simply drop into a pre-cut hole in the cabinet and are supported by the counters that surround it, and the cabinet below it. These units tend to have easier installations and are commonly found in the bathroom.
Flush Mount sinks provide a seamless way to attach your sink to your cabinet and countertop. In this style the bowl sits inside and below the countertop. They are typically used with laminate counter tops.
Undermount sinks are attached to the counter from underneath it. They are usually used with stone counter tops. These can be somewhat difficult to install but provide a clean, sleek look to your kitchen.
Pedestal sinks are a classic design. These types of sinks are built into and within a stand. They are one unit and offer a very easy installation.
Topmount sinks have a lip protruding out that rests on top of your counter. The sink basin is dropped into the counter.