An appoggiatura is

The same as a Grace note
A rapid alternation between the written note and the one above it
A dynamic marking typical of the barowue period
An ornamental note that is played on the beat and is usually rhythmatically equal to half the value of the note that follows it

1 answer

An appoggiatura is best described as an ornamental note that is played on the beat and is usually rhythmically equal to half the value of the note that follows it. It typically takes some of the time value of the note it precedes, unlike a grace note which is played quickly before the main note.