sliding board vs plaything

sliding board and plaything both are nouns.

Word	Noun	Adjective	Verb	Adverb
sliding board	Yes	No	No	No
plaything	Yes	No	No	No

As nouns, plaything is a hypernym of sliding board; that is, plaything is a word with a broader meaning than sliding board:

sliding board: plaything consisting of a sloping chute down which children can slide
plaything: an artifact designed to be played with

Other hypernyms of sliding board include toy.

sliding board (noun)	plaything (noun)
plaything consisting of a sloping chute down which children can slide	an artifact designed to be played with