I wish to know why aromatic hydrocarbons like benzene are called aromatic when they can be just called circular to avoid the confusion?
Aromaticity is a electronic property of a molecule, not a description of its shape. An aromatic molecule contains a circular system of conjugated π bonds and p orbitals that contains 4n+2 electrons, where n is an integer.
Benzene is aromatic: it has 6 electrons in a circular conjugated system (4n+2=6, n=1).
Cyclooctatetraene is not aromatic: it appears to have a circular conjugated system, but it contains 8 electrons (4n+2=8 would require n=3/2). This molecule actually adopts a non-planar geometry to avoid antiaromaticity.
Cyclohexane is not aromatic, even though it is circular: it does not have a conjugated electron system.
As @Kyle said aromaticity is an electronic property, not a description of shape and so circular would not be an appropriate description, particularly seeing as these molecules are not at all circular (benzene is hexagonal, for example).
The name 'aromatic' is a historical quirk. Supposedly it was used because many of the chemically aromatic substances know at the time happened to have notable aromas although wikipedia seems to dispute this. Several other reputable sites like this and this do support this view though so I'm not sure what the right answer is (or even if anybody knows).