What defines the structure of a Spenserian stanza?

A Spenserian stanza is characterized by having nine lines in total, composed of eight lines of iambic pentameter followed by a final line of iambic hexameter. This structure is distinctive and reflects the unique style of the poet Edmund Spenser. The combination of the eight pentameter lines, often linked by a specific rhyme scheme (ababbcbc), culminating in a longer ninth line, allows for a fluid yet intricate narrative form. This design effectively supports the thematic and lyrical elements often present in Spenser's epic poetry. The length and rhythm variation of the ninth line contributes to a sense of progression and resolution within the stanza, differentiating it from other stanza forms.