Lego vs plaything

Lego and plaything both are nouns.

Word	Noun	Adjective	Verb	Adverb
Lego	Yes	No	No	No
plaything	Yes	No	No	No

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

Lego: (trademark) a child's plastic construction set for making mechanical models
plaything: an artifact designed to be played with

Other hypernyms of Lego include toy.

Lego (noun)	plaything (noun)
(trademark) a child's plastic construction set for making mechanical models	an artifact designed to be played with