This is the 1024th most frequent Korean word.
식사를
"식사를" means "a meal" (in the object form).
Here, '식사를' is used as a direct object to mean 'meal' which is the action being performed (having the meal).
나는 친구와 함께 식사를 했습니다.
I had a meal with my friend.
In this sentence, '식사를' refers to the act of eating a meal, used in the context of asking if the action has been already done.
이미 식사를 하셨나요?
Have you already eaten a meal?
In this example, '식사를' also represents 'meal', but is used here in a temporal context to set up an action happening before having a meal.