Meaning of Common Metre in Urdu

Common metre or common measure — abbreviated as C. M. or CM — is a poetic metre consisting of four lines which alternate between iambic tetrameter (four metrical feet per line, with each foot consisting of an unstressed syllable followed by a stressed syllable) and iambic trimeter (three metrical feet per line, with each foot consisting of an unstressed syllable followed by a stressed syllable), rhyming in the pattern a-b-a-b.