| 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 |
Immediately |
Event occurs a single time (with no repetitions) as soon as possible after the scheduled or actual start of the overall event. |
| HS |
At nap time/bedtime |
Prior to beginning a regular period of extended sleep (this would exclude naps). Note that this might occur at different times of day depending on a person's regular sleep schedule. |
| WAKE |
Upon waking |
Upon waking up from a regular period of sleep, in order to start regular activities (this would exclude waking up from a nap or temporarily waking up during a period of sleep) |
| C |
Meal |
The event is to occur before, during, or after a meal. |
| CM |
Breakfast time |
The event is to occur before the morning meal. |
| CD |
Lunch time |
The event is to occur at lunch time. |
| CV |
Dinner time |
The event is to occur at dinner time. |
| AC |
Before Dinner |
The event is to occur before a meal. |
| ACM |
Before Breakfast |
The event is to occur before breakfast. |
| ACD |
Before Lunch |
The event is to occur before lunch. |
| ACV |
Before Dinner |
The event is to occur before dinner. |
| PC |
After Meal |
The event is to occur after meal. |
| PCM |
After Breakfast |
The event is to occur after breakfast. |
| PCD |
After Lunch |
The event is to occur after lunch. |
| PCV |
After Dinner |
The event is to occur after dinner. |