Book; plant (6)
I believe the answer is:
annual
I believe this is a double definition.
'book' is the first definition.
(annual is a kind of book)
'plant' is the second definition.
(annual is a type of plant)
(Other definitions for annual that I've seen before include "Plant that lives and dies within one year" , "(Of plant) living for a year or less" , "Regular publication" , "Twelve-monthly" , "Happening once each year" .)