The observance of a rule or custom is the practice of obeying it or following it. Observance is a fairly formal word.
You do not use observance to refer to the activity of watching someone or something carefully. The word you use is observation.
| Noun | 1. | observation - the act of making and recording a measurementmeasurement, measuring, mensuration, measure - the act or process of assigning numbers to phenomena according to a rule; "the measurements were carefully done"; "his mental measurings proved remarkably accurate" radio observation - an observation made with a radio telescope |
| 2. | observation - the act of observing; taking a patient look looking, looking at, look - the act of directing the eyes toward something and perceiving it visually; "he went out to have a look"; "his look was fixed on her eyes"; "he gave it a good looking at"; "his camera does his looking for him" monitoring - the act of observing something (and sometimes keeping a record of it); "the monitoring of enemy communications plays an important role in war times" sighting - the act of observing; "several sightings of enemy troops were reported" stargazing - observation of the stars | |
| 3. | observation - a remark expressing careful consideration | |
| 4. | observation - facts learned by observing; "he reported his observations to the mayor" fact - a piece of information about circumstances that exist or events that have occurred; "first you must collect all the facts of the case" scientific fact - an observation that has been confirmed repeatedly and is accepted as true (although its truth is never final) | |
| 5. | observation - the act of noticing or paying attention; "he escaped the notice of the police" attending, attention - the process whereby a person concentrates on some features of the environment to the (relative) exclusion of others mind - attention; "don't pay him any mind" remark - explicit notice; "it passed without remark" |