1) a strip of pigment that contrasts with immediately adjacent pigment or absence of pigment. A vertical band is a bar, a horizontal band is a stripe2) a vertical patch of pigment usually with well-defined margins, more extensive than a bar, running, for example, from the flank onto adjoining fins. Bands are sometimes defined as being oblique or diagonal in contrast to vertical bars3) a longitudinal patch of pigment, usually running along the side of the body, broader and less distinct than a stripe, q.v4) a region of similar structure or optical density laid down during growth of hard parts used in ageing. Also called mark, ring and zone5) a strip of pigment that encircles the body
Dictionary of ichthyology. 2009.