playground slide vs sliding board

playground slide and sliding board both are nouns.

Word	Noun	Adjective	Verb	Adverb
playground slide	Yes	No	No	No
sliding board	Yes	No	No	No

As nouns, playground slide and sliding board are synonyms defined as:

playground slide and sliding board: plaything consisting of a sloping chute down which children can slide

Other synonyms of playground slide include slide.

playground slide (noun)	sliding board (noun)
plaything consisting of a sloping chute down which children can slide	plaything consisting of a sloping chute down which children can slide