Observation (noun)

1. The process of observing or taking notice of something.
2. A remark or comment made as a result of observation.

Origin:

Middle english, from old french, from latin observatio, from observare to observe.

Examples:

1. The observation of the stars was his favorite hobby.
2. The teacher made an observation about the student's work.
3. His observation of the situation was accurate.
4. The scientists made detailed observations of the animals.
5. The observation deck offered a panoramic view of the city.