Castle Rackrent/Glossary/2

'''GLOSSARY 2. LET ALONE THE THREE KINGDOMS ITSELF.'''

&mdash;LET ALONE, in this sentence, means put out of consideration. The phrase, let alone, which is now used as the imperative of a verb, may in time become a conjunction, and may exercise the ingenuity of some future etymologist. The celebrated Horne Tooke has proved most satisfactorily, that the conjunction but comes from the imperative of the Anglo-Saxon verb (BEOUTAN) TO BE OUT; also, that IF comes from GIF, the imperative of the Anglo-Saxon verb which signifies TO GIVE, etc.