Book (6)
'book' is the definition.
(album is a kind of book)
This is all the clue.
(Other definitions for album that I've seen before include "It contains multiple musical tracks" , "Photograph/stamp book" , "A music record or a book of photos" , "Book of blank pages for collectables, memorabilia etc." , "Book for stamps/photos" .)
'book' is the definition.
(as in booking or reserving in advance)
This is all the clue.
(Other definitions for reserve that I've seen before include "cool" , "not in the front line" , "Husband - substitute" , "man on bench?" , "Twelfth man < 's coolness" .)
'book' is the definition.
(I know that book can be written as volume)
This is the entire clue.
(Other definitions for volume that I've seen before include "Three-dimensional space occupied by something" , "A book, especially one of a set" , "Space measured in cubic units" , "Book - sound level" , "Tome" .)