(of a statute or legal decision) Taking effect from a date in the past
(of an exhibition or compilation) Showing the development of an artist's work over a period of time
looking back [adj RETROSPECTIVELY] / a generally comprehensive exhibition, compilation, or performance of the work of an artist over a span of years [n -S]
Looking back on or dealing with past events or situations
means of or relating to the past or something that happened in the past.