The meaning of OBSERVE is to conform one's action or practice to (something, such as a law, rite, or condition) : comply with. How to use observe in a sentence. Synonym Discussion of Observe.

1. To take notice: stood by the window observing. 2. To say something; make a comment or remark: observed upon the unusual weather. 3. To watch or be present without participating actively: We …

[ + speech ] "I've always found German cars very reliable," he observed. [ + that ] She observed that it would soon be time to stop for lunch.

Something that's observed is seen or noted, especially as part of a scientific investigation. An observed side effect of a medication is one that's been scientifically proven.

To observe is to mark or be attentive to something seen, heard, etc.; to consider carefully; to watch steadily: to observe the behavior of birds, a person's pronunciation.

observed, adj. & n. meanings, etymology, pronunciation and more in the Oxford English Dictionary

If you observe someone or something, you watch them carefully. The professor observed the behaviour of babies.

To observe is to mark or be attentive to something seen, heard, etc.; to consider carefully; to watch steadily: to observe the behavior of birds, a person's pronunciation.

“The paint,” she observed [= remarked, said], “is already starting to peel.” Looking around at the shuttered houses, he observed [= commented] that the island was entirely different in the winter.

[transitive] observe something to obey rules, laws, etc. Will the rebels observe the ceasefire? The crowd observed a minute's silence (= were silent for one minute) in memory of those who had died.