"朝食" specifically means "breakfast," the first meal of the day typically eaten in the morning. It's the standard term for the morning meal. Often shortened to "朝ごはん" in casual speech.

一日の最初の食事である「朝ごはん」を指す言葉です。朝に食べる食事のことです。日常会話では「朝ごはん」もよく使われます。