Le mot anglais pour petit déjeuner est
breakfast

Définition en anglais

petit déjeuner
1. n-m. (chiefly France, and Belgium) breakfast (morning meal)

breakfast	©
1. n. Petit déjeuner.
2. v. (Désuet) Prendre le petit déjeuner.

breakfast	©
1. n. The first meal of the day, usually eaten in the morning.
You should put more protein in her breakfast so she will grow.
2. n. (by extension) A meal consisting of food normally eaten in the morning, which may typically include eggs, sausages, toast, bacon, etc.
We serve breakfast all day.
3. n. The celebratory meal served after a wedding (and occasionally after other solemnities e.g. a funeral).
4. n. (largely obsolete, outside, religion) A meal eaten after a period of (now often religious) fasting.
5. v. (intransitive) To eat the morning meal.
6. v. To serve breakfast to.