It can be used in several contexts:
* Lost object: "J'ai perdu mon téléphone." (I lost my phone.)
* Lost opportunity: "Il a perdu une chance unique." (He lost a unique opportunity.)
* Lost battle/game: "L'équipe a perdu le match." (The team lost the game.)
* Lost in thought: "Il était perdu dans ses pensées." (He was lost in thought.)
It can also be used figuratively, like "être perdu dans la ville" (to be lost in the city), which means to be unfamiliar with the surroundings.