English Reference
verb

observe

v.
US /əbˈzɝv/ UK /ɒbzˈɜːv/ ob·serve UK spelling observes

  1. 01 B2 Upper Intermediate Science

    to watch someone or something carefully, often to learn something new.

    to watch or monitor something with attention to detail, often for scientific or investigative purposes.

    Simple

    The scientists stayed up all night to observe the behavior of the birds.

    In context

    Researchers spent several months in the field to observe how the local wolf population interacted with neighboring packs during the winter.

    Usage

    Often used with a direct object or a 'that' clause.

  2. 02 B2 Upper Intermediate Formal

    to obey a law, a rule, or a religious custom.

    to comply with or adhere to a law, regulation, or religious tradition.

    Simple

    Drivers must observe the speed limit to keep the roads safe.

    In context

    The company failed to observe the safety regulations, resulting in a significant fine from the environmental protection agency.

    Usage

    Transitive; takes a direct object representing the rule or law.

  3. 03 B2 Upper Intermediate Formal

    to mark or celebrate a special day, like a holiday.

    to acknowledge or celebrate a holiday, anniversary, or significant event through traditional practices.

    Simple

    Many people observe a moment of silence to remember the soldiers.

    In context

    The embassy will be closed on Monday as the staff observe the national holiday of their home country.

  4. 04 C1 Advanced Formal

    to say or write a remark about something you have noticed.

    to make a verbal or written remark; to comment on a situation or fact.

    Simple

    "It is getting quite late," she observed as she looked at the clock.

    In context

    The critic observed that the director's latest film lacked the emotional depth of his earlier masterpieces.

    Usage

    Often introduces a direct quote or a 'that' clause.

Usage additionally observe · directly observe · finally observe

After spending hundreds of hours observing harbor porpoises from the pedestrian walkway of the Golden Gate Bridge, William Keener learned to say “porpoise” in a dozen languages.

Smithsonian Magazine· 14 Aug 2026

Instead, I observe Orion KL's chemistry from Earth with radio telescopes.

Phys.org· 16 Aug 2026

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”).

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Origin ine-pro *ser-
Level B2 · Upper Intermediate
Frequency Common
Updated