1Indicates that something has already happened; similar to 'already', used to show completion or that a fact is established.
会議はすでに始まっている。
The meeting has already started.
その本はすでに読んだ。
I've already read that book.
すでに支払いは済ませてあります。
The payment has already been made.
2Indicates that something occurred prior to a certain point; means 'previously' or 'before'.
彼はすでにその会社を辞めていた。
He had already left that company.
その噂はすでに村中に広まっていた。
That rumor had already spread throughout the village.
このデータはすでに収集済みだ。
This data was collected beforehand.
3A formal usage emphasizing that a fact is already firmly and undeniably established — close to 'it is already the case that...' or 'needless to say'.
すでに勝敗は決まっていたも同然だった。
The outcome was already all but decided.
すでに手遅れであることは誰の目にも明らかだった。
It was already obvious to everyone that it was too late.