The description of the word you requested from the astronomical dictionary is given below.
convectio = [Latin] bring together, from con- = with, and vectio = carry; zona [Latin] from zoone = [Greek] girdle
The convection zone is a layer in the Sun that reaches from just below the surface down to about 130,000 miles (183,000 km) below the surface. The convection zone contains about 2/3 of the Sun's volume (up to the visible surface) but only about 1/60 of the Sun's mass. In this layer the energy of the Sun is transported to the surface by convection. The temperature inside this layer is thought to vary between 2.0 million and 6500 K (4 million and 12,000 degrees F, 2.2 million and 6200 degrees Centigrade), and the density between 100 times more and 4,000 times less than that of air at the Earth's surface.
Many other stars also have one more more convection zones, which may also be far below the surface, or even in the core of the stars.