three meals (a day)
Refers to the three daily meals: breakfast, lunch, and dinner. Often used in contexts like 三食付き (with three meals included) or 一日三食 (three meals a day).
This hotel includes three meals.
I eat three proper meals a day.
食事 is a general term for a meal, while 三食 specifically means three meals (usually per day).
Compound of 三 (three) and 食 (meal/eating).