Note duration, also called note value, refers to how long a note is sounded; that is, whether it is a whole note, half note, quarter note, etc. It is indicated in standard music notation by the image of the note, including whether the notehead is hollow or filled in, whether it has a stem, and how many flags, if any, it has as well as by whether it is a dotted note (directly followed by one or more dots). This contrasts with a note's pitch, which is indicated by its vertical position on the staff.