A grace note is an ornamental note (see ornaments) usually played quickly before the beat. It is shown in small type to indicate that its time value isn't counted in the rhythm of the bar. On its own, a single grace note usually indicates an appoggiatura or an acciaccatura. When grace notes occur in groups, they may indicate any of several different classes of ornamentation, depending on interpretation.
A grace-note bend, played on a guitar, is a bend that makes an immediate transition up to the desired pitch, without sounding the fretted note. The fretted note is written in notation but without a symbol describing note duration.