takoyaki vs solid food

takoyaki and solid food both are nouns.

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

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

takoyaki: a ball-shaped Japanese snack made of a wheat flour-based batter and cooked in a special moulded pan
solid food: any solid substance (as opposed to liquid) that is used as a source of nourishment

Other hypernyms of takoyaki include food.

takoyaki (noun)	solid food (noun)
a ball-shaped Japanese snack made of a wheat flour-based batter and cooked in a special moulded pan	any solid substance (as opposed to liquid) that is used as a source of nourishment