A time signature (also known as meter signature,[1]metre signature,[2] and measure signature)[3] is an indication in music notation that specifies how many note values of a particular type are contained in each measure (bar). The time signature indicates the meter of a musical movement at the bar level.
In a music score the time signature appears as two stacked numerals, such as 4 4 (spoken as four–four time), or a time symbol, such as (spoken as common time). It immediately follows the key signature (or if there is no key signature, the clef symbol). A mid-score time signature, usually immediately following a barline, indicates a change of meter.
Most time signatures are either simple (the note values are grouped in pairs, like 2 4, 3 4, and 4 4), or compound (grouped in threes, like 6 8, 9 8, and 12 8). Less common signatures indicate complex, mixed, additive, and irrational meters.
Basic time signatures: 4 4, also known as common time(); 2 2, alla breve, also known as cut time or cut-common time (); 2 4; 3 4; and 6 8
^Alexander R. Brinkman, Pascal Programming for Music Research (Chicago: University of Chicago Press, 1990): 443, 450–63, 757, 759, 767. ISBN0226075079; Mary Elizabeth Clark and David Carr Glover, Piano Theory: Primer Level (Miami: Belwin Mills, 1967): 12; Steven M. Demorest, Building Choral Excellence: Teaching Sight-Singing in the Choral Rehearsal (Oxford and New York: Oxford University Press, 2003): 66. ISBN0195165500; William Duckworth, A Creative Approach to Music Fundamentals, eleventh edition (Boston, MA: Schirmer Cengage Learning, 2013): 54, 59, 379. ISBN0840029993; Edwin Gordon, Tonal and Rhythm Patterns: An Objective Analysis: A Taxonomy of Tonal Patterns and Rhythm Patterns and Seminal Experimental Evidence of Their Difficulty and Growth Rate (Albany: SUNY Press, 1976): 36–37, 54–55, 57. ISBN0873953541; Demar Irvine, Reinhard G. Pauly, Mark A. Radice, Irvine’s Writing about Music, third edition (Portland, Oregon: Amadeus Press, 1999): 209–210. ISBN1574670492.
^Henry Cowell and David Nicholls, New Musical Resources, third edition (Cambridge and New York: Cambridge University Press, 1996): 63. ISBN0521496519 (cloth); ISBN0521499747 (pbk); Cynthia M. Gessele, "Thiéme, Frédéric [Thieme, Friedrich]", The New Grove Dictionary of Music and Musicians, second edition, edited by Stanley Sadie and John Tyrrell (London: Macmillan Publishers, 2001); James L. Zychowicz, Mahler's Fourth Symphony (Oxford and New York: Oxford University Press, 2005): 82–83, 107. ISBN0195181654.
^Edwin Gordon, Rhythm: Contrasting the Implications of Audiation and Notation (Chicago: GIA Publications, 2000): 111. ISBN1579990983.