The stanza in the sonnet has been defined as a set of poetic lines followed after proem and be the same meter as that of proem in complete stanza. but in rhyme scheme different from that meter. The couplet is defined as set of poetic lines that followed the stanza and be as the same meter as that of stanza. but with different rhyme scheme. https://www.chiggate.com/shades-eq-gloss-07m-driftwood-for-sale/