n. In prosody, two lines in immediate succession, usually but not necessarily of the same length, forming a pair, and generally marked as such by riming with each other.n. In music, two equal notes inserted in the midst of triple rhythm to occupy the time of three; a temporary displacement of triple by duple rhythm.n. One of a pair, as of twins; a twin.n. In Gothic arch., a double window; one having two lights only and these of the same size and style.