This is the 173rd most frequent Japanese word.
限定
"Limited" or "exclusive."
Here, '限定' indicates that the discount is temporally restricted to the end of the month.
この特別な割引は今月末まで限定です。
This special discount is limited until the end of this month.
In this sentence, '限定' is used to specify that the event is exclusively accessible to members.
会員限定のイベントに参加することができます。
You can attend the members-only event.
The word '限定' is used here to indicate that the lunch menu is available only during the weekend, emphasizing exclusivity and temporal limitation.