1911 Encyclopædia Britannica/Alone

ALONE. This adjective or adverb requires no definition for its meaning of “by oneself” or “solitary”; but its etymological history, as simply a combination of the words “all” and “one” is rather curious (compare the Ger. allein). “Lone” is merely a clipped form of the word, and so “lonely.” The New English Dictionary traces the English word back to the year 1300.