The comb-over is a hair-grooming practice in which a balding man brushes a few strands of hair over a wide expanse of his bald head, usually starting with an unnatural part. Sometimes he cements the hair in place with oil or a styling product. The hallmark of a comb-over is that the combed-over hair covers only a small portion of the available scalp area. Much as a piece of avant-garde music might call attention to the silences between successive notes, a comb-over directs your helpless attention to the hair that is no longer there.
Comb-overs are a somewhat mysterious phenomenon. Although most men find them distasteful, many still end up adopting them in later years of baldness. Sociological thinkers (and people with a great deal of extra time on their hands) suggest that combover practitioners fall prey to the sorites paradox. Essentially, the sorites paradox describes how small steps that seem sensible on their own can lead to an absurd outcome. In the case of comb-overs, the victim may begin moving the part of his hair by a small amount to add fullness to a region of thinning hair. Only as the process of baldness accelerates does this become a futile attempt to hide a glaring patch of skin under the last few stragglers of hair. Incidentally, the Japanese call men with comb-overs barcode men, because the lines of neatly aligned hair resemble barcode symbols.
Source of Information : Oreilly - Your Body Missing Manual (08-2009)