The comparative is the form of an adjective or adverb which denotes
the degree or grade by which a person, thing, or other entity has a
property or quality greater or less in extent than that of another.
In English the structure of a comparative consists normally of the
positive form of the adjective or adverb, plus the suffix -er, or
(especially in the case of longer words) the modifier "more" (or
"less") before the adjective or adverb. The form is usually completed
by "than" and the noun which is being compared, e.g. "he is taller
than his father is", or "the village is less picturesque than the
town near by is". (http://en.wikipedia.org/wiki/Comparative 17.11.06)