tempo vs meno mosso

tempo and meno mosso both are nouns.

Word	Noun	Adjective	Verb	Adverb
tempo	Yes	No	No	No
meno mosso	Yes	No	No	No

As nouns, meno mosso is a hyponym of tempo; that is, meno mosso is a word with a more specific, narrower meaning than tempo:

Other hyponyms of tempo include accelerando, allegretto, allegro, andante, rubato.

tempo (noun)	meno mosso (noun)
the rate of some repeating event	played at reduced speed; less rapid
(music) the speed at which a composition is to be played