What are Square Centimeters?
A square centimeter is the area of a square 1 centimeter on each side, which is 100 square millimeters or 0.0001 square meters. A postage stamp is a few square centimeters.
What are Hectares?
A hectare is 10,000 square meters, or about 2.47 acres. It is the usual metric unit for land, so farms, parks and forests are measured in hectares.
A hectare is the area of a square 100 meters on each side. The name is 'hecto-' plus are, an are being 100 square meters, so a hectare is 100 ares.