yoghurt vs solid food

yoghurt and solid food both are nouns.

Word	Noun	Adjective	Verb	Adverb
yoghurt	Yes	No	No	No
solid food	Yes	No	No	No

As nouns, solid food is a hypernym of yoghurt; that is, solid food is a word with a broader meaning than yoghurt:

yoghurt: a custard-like food made from curdled milk
solid food: any solid substance (as opposed to liquid) that is used as a source of nourishment

Other hypernyms of yoghurt include food, dairy product.

yoghurt (noun)	solid food (noun)
a custard-like food made from curdled milk	any solid substance (as opposed to liquid) that is used as a source of nourishment