A Chiastic envelope is a stanza or poem structured in chiastic (ABBA) or mirrored pattern, where the first and last elements correspond, and the second and penultimate echo each other, creating a symmetrical frame; this form, common in classical and Hebrew poetry, emphasizes balance, return, and thematic encapsulation, as in the enveloping quatrains of Tennyson or the concentric logic of Sapphic stanzas.

Stanza structure beginning and ending with similar elements enclosing contrasting middle, creating ABBA envelope pattern with internal crossing. Combines envelope form with chiastic inversion for complex symmetry.