observe
v.v. to watch something or someone carefully to learn more about them. It can also mean to follow a rule or a custom.
v. to watch or examine something scientifically or attentively; to comply with a law, custom, or religious ritual.
Scientists observe the behavior of birds in the wild.
The security guards observe the crowd through cameras to ensure everyone stays safe during the concert.
While researchers observe the chemical reaction for any signs of instability, the staff must strictly observe all safety protocols to prevent an accidental spill.
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 (sarwa, “weapons, armour”), Old English searu (“device”).
The verb is transitive and takes a direct object. When used to mean 'following a rule', it is more formal than 'follow' or 'obey'.
observe to the rulesobserve the rulesObserve is a transitive verb and does not take the preposition 'to'.