Lifetime, One Lifetime, Generation, One Generation
noun
This word has the kanji for one and period. You only have one period to live in so this is the only lifetime you get. Unless you're reborn, but that will probably be in the next age, not this one. So one lifetime for you!
いちだい
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
あのイタリアンレストランは一代でクローズしてしまった。
After a generation, that Italian restaurant has closed.
オーナーは一代でこのホテルを日本一のホテルにしました。
The owner has made this hotel the best hotel in Japan in one generation.
父は一代で小さいコンビニエンスストアを大きなデパートにしたんです。
In one generation, my father turned a small convenience store into a big department store.