Articulation
The way successive notes are connected or separated, such as legato or staccato.
What it means
Articulation describes how successive notes are connected to or separated from one another. It determines whether a melody flows smoothly from one note to the next, sounds clearly detached, or falls somewhere in between, and it shapes the character of a musical line quite independently of pitch, duration, or dynamics.
The two poles of articulation are legato, smooth and unbroken playing, and staccato, short and clearly detached playing. Between them lie many gradations, such as portato or non legato, which shape the transition between the two extremes.
In the notation
Articulation is notated with its own set of signs: a slur over several notes calls for legato, a dot above or below the notehead for staccato, a wedge for staccatissimo or marcato depending on context, and a horizontal dash for tenuto. These signs are distinct from ties, which extend a note across a barline, even though both appear graphically as a curved line.
Musical use
Along with dynamics, tempo, and phrasing, articulation is one of the most important means by which music gains expression. On string instruments it is closely tied to bowing, on wind instruments to tonguing, and on keyboard instruments to touch and pedaling. In vocal music its counterpart is the distribution of syllables across notes, as in a melisma, where several notes fall on a single syllable.
Historically, the treatment of articulation varied considerably: Baroque music generally calls for a sharper, more clearly separated style than Romantic music, which often favors continuous legato. Articulation is distinguished from phrasing, which concerns larger musical units of meaning, while articulation governs the connection of individual, neighboring notes.
Performance practice
Practice the same passage deliberately in different articulations to feel their effect before settling on one. Make sure legato does not blur into indistinctness and staccato does not become too hard; both should stay controlled in tone. Where articulation marks are missing or ambiguous, take your cue from the work's style and from comparable passages by the same composer.