What does 有効 mean?
有効 is a Japanese noun meaning “valid, effectual” in English. It can also be translated as “yuko (judo)” depending on context. It is written as 有効 in kanji, ゆうこう in hiragana, and yuukou in romaji. This word is part of JLPT N3 vocabulary.
Example sentence
その切符は一週間有効です。
The ticket is valid for a week.