Other forms: observed, observing, observes
To observe something is to watch it carefully, over time, in order to learn from it. A nurse observes a patient overnight; a birdwatcher observes a nest from a hide; a trainee teacher sits at the back of the room and observes the class.
Two other senses are worth having. To observe is also to remark — "it is colder than yesterday", he observed — which is why a written comment is called an observation. And to observe a rule, a custom or a holiday is to keep it: observe the speed limit, observe a minute's silence, observe the fast. The two nouns split along those lines and get mixed up constantly: observance is about keeping rules, observation is about watching. Someone described as observant either notices a great deal or is strict about religious practice, and only the sentence tells you which. Observe is formal; in conversation you would just say watch.
1verbobserveTo watch something carefully over time in order to learn from it.~36%
“Students observe the surgery from the gallery above the theatre.”
2verbnoticeTo notice something.~2%
“He observed a thin crack running the length of the ceiling.”
formal in this meaning — an editor’s judgement
3verbremarkTo say something as a remark.~2%
“The taxi is late, she observed, without looking up from her book.”
formal in this meaning — an editor’s judgement
4verbkeepTo obey a rule or keep a custom.~60%
“The town still observes the old market day in November.”
formal in this meaning — an editor’s judgement
Shares are an estimate: a language model read 24 sentences found in the wild and placed 24 of them on a sense — a count of our sample, not a measurement of English.
Latin observō is ob-, "before", plus servō, "to keep" — to keep a thing in front of you. Behind servō lies the Proto-Indo-European root ser-, "to guard", so watching and guarding begin as one act: a guard watches, and a watcher keeps. That is why the single English verb still covers observing a patient and observing a rule. The same root left Old English searu, "device", and the Gothic word for weapons.
Proto-Indo-European
*ser- (guard)
Proto-Indo-European
*ser- — to guard
Latin
observō — to watch
Old French
observer
Middle French
observer
English, today
observe
Built from
From Middle French observer, from Old French observer, from Latin observō (“to watch”), from ob- (“before”) + servō (“to keep”), from Proto-Indo-European ser- (“to guard”). Cognate with Gothic 𐍃𐌰𐍂𐍅𐌰 (“weapons, armour”), Old English searu (“device”).
Etymology from Wiktionary, CC BY-SA