observer

American  

[uhb-zur-ver] / əbˈzɜr vər /

noun

1. someone or something that observes.

2. a delegate to an assembly or gathering, who is sent to observe and report but not to take part officially in its activities.

3. U.S. Air Force.

   1. a member of an aircrew, other than the pilot, holding an aeronautical rating.

   2. a person who maintains observation in an aircraft during flight.

4. Also called air observer,.  Also called aircraft observer.  U.S. Army. a person who serves in an aircraft as a reconnoiterer and directs artillery fire.

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observer British  

/ əbˈzɜːvə /

noun

1. a person or thing that observes

2. a person who attends a conference solely to note the proceedings

3. a person trained to identify aircraft, esp, formerly, a member of an aircrew

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Other Word Forms

• interobserver
  noun
• observership
  noun

Etymology

Origin of observer

First recorded in 1545–55; observe + -er ¹

Explanation

An observer is someone who watches or pays attention to something — if you're an observer of current events, you probably watch the news and read the newspaper every day to keep up with what's going on. You can be an accidental observer of something, like pedestrians who happen to witness an accident and become observers of it. Another kind of observer is one who notices things deliberately, like political observers who watch and comment on various events. Many newspapers once had the word observer in their names, from this second sense of the word. The verb observe has a Latin root, observare, which means "watch over, note, heed, or attend to."

Example Sentences

The European Union's election observer mission nonetheless gave the election a clean bill of health.

From Barron's • May 8, 2026

To resolve this, scientists usually propose that when a quantum system is measured or interacts with an observer, its wavefunction collapses into a single outcome.

From Science Daily • May 3, 2026

Harrison Phipps, 23, who has severe to profound hearing loss in both ears, is helped by an observer off the mat.

From BBC • Apr. 22, 2026

Jim Grant, the long-time markets observer, says there’s a big disconnect between official economic data and consumer perceptions of it.

From MarketWatch • Apr. 14, 2026

Any observer can work out precisely what time and position any other observer will assign to an event, provided he knows the other observer’s relative velocity.

From "A Brief History of Time: And Other Essays" by Stephen Hawking

Related Words

• bystander
• onlooker
• viewer
• watcher
• witness