sketch block vs sketchbook

sketch block and sketchbook both are nouns.

Word	Noun	Adjective	Verb	Adverb
sketch block	Yes	No	No	No
sketchbook	Yes	No	No	No

As nouns, sketch block and sketchbook are synonyms defined as:

sketch block and sketchbook: a book containing sheets of paper on which sketches can be drawn

Other synonyms of sketch block include sketch pad.

sketch block (noun)	sketchbook (noun)
a book containing sheets of paper on which sketches can be drawn	a book containing sheets of paper on which sketches can be drawn