In poetic forms, a couplet is primarily defined by what characteristic?

A couplet is primarily defined by the characteristic of having a rhyme and meaning connection between two lines. This means that in a couplet, the two lines typically rhyme with one another and often express a cohesive thought or idea. The rhyme creates a musical quality in poetry, while the connection in meaning enhances the overall message or theme being conveyed in those two lines.

This focus on rhyme and the interconnection of thoughts is what distinguishes a couplet from other poetic forms, which may not have the same structural requirements. The other options, such as the number of stanzas, the overall theme, or the use of contraction, do not specifically relate to what constitutes a couplet, making them less relevant in defining this particular form of poetry.