A stanza of four lines, or a group of four rhyming lines within a sonnet. Varieties of quatrain stanza are distinguished by metre and rhyme scheme. The quatrain of rhymed pentameters is known as the ‘heroic quatrain’. More often found are those employing four‐stress lines only (known as ‘long measure’) or in combination with three‐stress lines arranged 4343 (‘common measure’, as in many ballads) or 3343 (‘short measure’, as in some hymns). The principal rhyme schemes are a b c b (especially in ballads), a b a b, a a b b, and a b b a; the quatrain of octosyllabic lines rhyming a b b a is sometimes called the In Memoriam stanza.