MusicMeasure

MusicMeasure[{event1, event2, ...}]
MusicMeasure[events, properties]

represents one measure containing MusicNote, MusicRest and MusicChord events.

MusicMeasure[{
  MusicNote["C4", 1/4],
  MusicNote["E4", 1/4],
  MusicRest[1/4],
  MusicChord[{"C4", "E4", "G4"}, 1/4]
}]

Container properties include "NoteList", "TimeSignature", "KeySignature", "MusicTempo" and "Instrument".

MusicMeasure[
  {"C4", "D4", "E4"},
  <|
    "TimeSignature" -> MusicTimeSignature[3, 4],
    "Instrument" -> "Flute"
  |>
]

The instrument and tempo are inherited by contained events unless a more specific value is present.

Playback

A measure can be used as a Sound primitive or collected into a MusicVoice:

Sound[
  MusicMeasure[
    {"C4", "E4", "G4", "C5"},
    <|"Instrument" -> "Marimba"|>
  ]
]

See the Wolfram Language reference for measure partitioning and tie behavior.