In describing his grandfather's nose, Rushdie uses vivid imagery. This quote also is an example of simile and metaphor - "My grandfather's nose: nostrils flaring, curvaceous as dancers. Between them swells the nose's triumphal arch, first up and out, then down and under, sweeping in to his upper lip with a superb...flick".
Grandfather's nose is symbolic of his role as patriarch of a dynasty, and all his descendants bear this identifying mark as well - "Doctor Azia's nose...established incontrovertibly his right to be a patriarch...a nose to start a family on...there'd be no mistaking whose brood they were".
Rushdie also uses some delightful play on words in describing Grandfather's nose - "You could cross a river on that nose...its bridge was wide".
(All quotes from Chapter 1)