allein

Allein is a German term that functions as both an adverb and an adjective, meaning "alone," "solitary," or "sole/only." It is used to indicate the absence of others or to express exclusivity. For example, "Ich bin ganz allein" translates as "I am completely alone," while "das ist meine alleinige Entscheidung" means "that is my sole decision."

Historically, allein is of Germanic origin and is attested in Middle High German as allein. In modern standard German it appears in various grammatical forms and can combine with other words to form compounds that emphasize singleness or exclusivity.

As a proper noun, Allein may appear as a surname or in toponyms in German-speaking regions, though such uses are relatively uncommon compared with the everyday usage of the word as a common term.

Because of the similarity in spelling to related forms such as alleine, the word is sometimes encountered in dialectal or regional usage, where nuances between allein and alleine can differ. In contemporary German, beide forms are understood, with allein often carrying a more formal or emphatic sense, while alleine tends to be used for more everyday or emphatic solitary situations.