solid food; solids
Refers to food in solid form, as opposed to liquid or soft food. Often used in medical, nutritional, or baby-care contexts.
The baby cannot eat solid food yet.
Please avoid solid food for a while after the surgery.
離乳食 is baby weaning food, which can be soft or pureed, while 固形食 is specifically solid food.
Compound of 固形 (solid) + 食 (food, eating). The exact historical derivation is uncertain, but the word is a straightforward modern compound.