Definition of lookbook:
(n) :
(fashion, colloquial) A contiguous showcase of still images of a fashion designer or fashion brand’s collection.
(n) :
(fashion, colloquial) A comprehensive directory of fashion-related companies and people, such as fashion designers, industry figures, brands and retail stores.
(n) :
(film) A showcase of photographs etc. describing how a film should look.
(v) :
(fashion, colloquial) To locate fashion-related information by means of a directory.