| Code | Display | Definition |
| MORN |
Morning |
Event occurs during the morning. The exact time is unspecified and established by institution convention or patient interpretation. |
| MORN.early |
Early Morning |
Event occurs during the early morning. The exact time is unspecified and established by institution convention or patient interpretation. |
| MORN.late |
Late Morning |
Event occurs during the late morning. The exact time is unspecified and established by institution convention or patient interpretation. |
| NOON |
Noon |
Event occurs around 12:00pm. The exact time is unspecified and established by institution convention or patient interpretation. |
| AFT |
Afternoon |
Event occurs during the afternoon. The exact time is unspecified and established by institution convention or patient interpretation. |
| AFT.early |
Early Afternoon |
Event occurs during the early afternoon. The exact time is unspecified and established by institution convention or patient interpretation. |
| AFT.late |
Late Afternoon |
Event occurs during the late afternoon. The exact time is unspecified and established by institution convention or patient interpretation. |
| EVE |
Evening |
Event occurs during the evening. The exact time is unspecified and established by institution convention or patient interpretation. |
| EVE.early |
Early Evening |
Event occurs during the early evening. The exact time is unspecified and established by institution convention or patient interpretation. |
| EVE.late |
Late Evening |
Event occurs during the late evening. The exact time is unspecified and established by institution convention or patient interpretation. |
| NIGHT |
Night |
Event occurs during the night. The exact time is unspecified and established by institution convention or patient interpretation. |
| PHS |
After Sleep |
Event occurs [offset] after subject goes to sleep. The exact time is unspecified and established by institution convention or patient interpretation. |
| IMD |
Immediate |
Event occurs a single time (with no repetitions) as soon as possible after the scheduled or actual start of the overall event. |