1the period after a meal; after eating (often used to indicate timing for taking medicine, etc.).
薬は食後に飲んでください。
Please take the medicine after meals.
食後に歯を磨く習慣は健康に良い。
It's good for your health to brush your teeth after meals.
会議は食後すぐに始めます。
The meeting will start immediately after the meal.