Musical notation provides the visual framework for communicating pitch and rhythm. The treble clef, also called the G clef, curls around the second line of the staff to indicate that line is G4, and is used for higher-pitched instruments and voices as well as the right hand in piano music. The bass clef, also called the F clef, places two dots around the fourth line to mark it as F3, and is used for lower-pitched instruments, voices, and the left hand in piano music. Several symbols modify pitch within a measure: the sharp (♯) raises a note by a half step, the flat (♭) lowers it by a half step, the natural (♮) cancels a previous accidental or key signature alteration, and the double sharp and double flat alter a note by a whole step.
Other symbols affect duration and articulation. A fermata placed over a note or rest instructs the performer to hold it longer than its written value, at the performer's or conductor's discretion. Staccato, marked by a dot above or below a note, directs the performer to play the note short and detached, typically held for about half its written value. Legato indicates that notes should be played smoothly and connected, often marked by a slur, a curved line over notes of different pitches. A tie, by contrast, connects two notes of the same pitch to combine their durations into one sustained note. Repeat signs are double barlines with two dots that indicate a section should be played again, with first and second endings directing different passages on each repetition. D.C. (Da Capo) instructs the performer to return to the beginning of the piece, and D.S. (Dal Segno) instructs a return to the segno sign; both are often followed by al Fine or al Coda to guide the performer through the structure.
Dynamics and tempo shape the emotional contour of a piece. The dynamic marking piano (p) means softly and forte (f) means loudly; doubling either, as in pianissimo (pp) or fortissimo (ff), makes them more extreme. Mezzo piano (mp) means moderately soft and mezzo forte (mf) means moderately loud. A crescendo gradually increases volume, marked by an opening hairpin, while a decrescendo, also called a diminuendo, gradually decreases volume, marked by a closing hairpin. Common tempo markings include Largo (very slow, around 40–60 BPM), Adagio (slow and expressive, around 66–76 BPM), Andante (a moderately slow walking pace, around 76–108 BPM), Allegro (fast and lively, around 120–156 BPM), and Presto (very fast, around 168–200 BPM).
Form organizes music into larger structures. Binary form consists of two contrasting sections, often used in Baroque dances like gavottes and bourées. Ternary form features a returning first section after a contrasting middle, providing symmetry and closure, and is common in da capo arias, minuets with trios, and many pop songs. Rondo form alternates a recurring main theme with contrasting episodes, such as A–B–A–C–A, and was a popular final-movement form in Classical sonatas and concertos. Sonata form structures entire movements in three main sections: an exposition introducing two contrasting themes in different keys, a development that transforms and explores those themes, and a recapitulation that restates both themes in the home key. Theme and variations presents a melody and then repeats it with successive modifications to melody, harmony, rhythm, tempo, key, or orchestration. The 12-bar blues form consists of three four-bar phrases following the chord pattern I–I–I–I / IV–IV–I–I / V–IV–I–I and typically uses an AAB lyrical structure in which the first line is stated and then repeated before a contrasting third line.