Emily Dickinson Lexicon

AL-EX-AN'DRINE, or AL-EX-AN'DRI-AN, n.

A kind of verse, consisting of twelve syllables, or of twelve and thirteen alternately; so called from a poem written in French on the life of Alexander. This species of verse is peculiar to modern poetry, but well adapted to epic poems. The Alexandrine in English consists of twelve syllables, and is less used than this kind of verse is among the French, whose tragedies are generally composed of Alexandrines. – Pope. Dryden.