A likeness of a particular person. Also taller than wide — the orientation named for the pictures it suits.
Latin protrahere (to draw forth, reveal), from pro- (forth) + trahere (to draw), via French portrait; a likeness drawn forth of one particular person, and by extension the tall orientation the pictures of a person best suit.
A likeness drawn of one particular person, and also the taller-than-wide orientation the pictures of a person tend to suit.