To restrict or limit something; to confine within a certain range or amount (transitive use).
参加者数を先着100名に限ると告知した。
They announced that participants would be limited to the first 100 people.
このクーポンの利用を一人一回に限る。
The use of this coupon is restricted to one per person.
図書館は利用時間を夜10時までに限った。
The library limited its hours of use to 10 PM.
To be restricted or limited to something; to indicate that something applies only to a specific group or condition (intransitive use).
この割引は学生に限られている。
This discount is limited to students.
応募資格は日本在住者に限ると書かれている。
It says that eligibility to apply is limited to residents of Japan.
定員は50人に限られているので、早めに申し込んでください。
Capacity is limited to 50 people, so please register early.
(Idiomatic) '〜は…に限る' — to say that something is the best or most advisable option in a situation ('... is best').
寒い日は鍋に限る。
On cold days, hot pot is the best.
風邪をひいたときは無理をせずに寝るに限る。
When you have a cold, it's best to rest and not overdo it.
夏はやっぱり海に行くに限るね。
In summer, going to the beach is definitely the best, huh.