A beit (also spelled bait) is a unit of poetry of Arabic poetry and Persian roots.

As a noted 19th century folklorist William Alexander Clouston wrote, beit, or line, is usually but improperly translated "couplet". Further:¹

The word beit signifies literally "a house", but by analogy "a tent" (and from this we may fairly conclude at least this fundamental part of Arabic prosody to have originated with the Bedouins or Arabs of the desert, as it is only they who would be likely to call a tent a house), the verse being whimsically regarded by the Arabs as an edifice; and this simile is carried out in the nomenclature of the different parts of the line, one foot being called "a tent-pole", another "tent-peg", and the two hemistichs of the verse being known as the folds or leaves of the double-door of the tent. Eact beit is divided into two hemistichs of equal length, each containing two, three, or four feet, or from 16 to 32 sylables.

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