pocket edition vs softback book

pocket edition and softback book both are nouns.

Word	Noun	Adjective	Verb	Adverb
pocket edition	Yes	No	No	No
softback book	Yes	No	No	No

As nouns, softback book is a hypernym of pocket edition; that is, softback book is a word with a broader meaning than pocket edition:

Other hypernyms of pocket edition include paper-back book, paperback, paperback book, soft-cover, soft-cover book, softback.

pocket edition (noun)	softback book (noun)
pocket-sized paperback book	a book with paper covers