There are many different kinds of ice.
Land ice is ice grounded on land, and above sea level. If this ice melts, it contributes to sea level rise. Glaciers and ice sheets are the most common kind of land ice.
The Antarctic Ice Sheet is surrounded by many other kinds of ice. Sea ice is floating, frozen sea water. It melts away seasonally, blows around in the wind, and is not attached to the land. In the Arctic, the winter extent of sea ice is decreasing over time; in the Antarctic, increased wind strength is dispersing a thinner layer of sea ice over a wider area.
Ice shelves are the floating extensions of land ice. Where large ice streams meet the ocean in Antarctica, they start to float (the point at which they start to float is the grounding line).
Icebergs are the bits of ice that calve away from marine-terminating or lake-terminating glaciers and ice sheets. They float away into the ocean. Increased calving of land ice into the ocean contributes to sea level rise.
This video explains about sea ice.