observation

WordReference Random House Learner's Dictionary of American English © 2026

ob•ser•va•tion /ˌɑbzɜrˈveɪʃən/   n. 

1. [countable] an act or instance of watching attentively.
2. the ability or habit of observing or noticing things:
   [uncountable] powers of observation.
3. an act or instance of watching carefully or noting something for a scientific or other special purpose:
   [countable] a classroom observation of a teacher by the headmaster.
   [uncountable* under + ~]
   to keep the patient under observation until he recovers.
4. a judgment made on the basis of what one has observed:
   [countable] He shared her observations on how people behaved.
5. [countable] a remark;
   comment.

See -serv-².

WordReference Random House Unabridged Dictionary of American English © 2026

ob•ser•va•tion  (ob′zûr vā′shən), n. 

1. an act or instance of noticing or perceiving.
2. an act or instance of regarding attentively or watching.
3. the faculty or habit of observing or noticing.
4. notice:
   to escape a person's observation.
5. an act or instance of viewing or noting a fact or occurrence for some scientific or other special purpose:
   the observation of blood pressure under stress.
6. the information or record secured by such an act.
7. something that is learned in the course of observing things:
   My observation is that such clouds mean a storm.
8. a remark, comment, or statement based on what one has noticed or observed.
9. the condition of being observed.
10. [Navig.]
    • Naval Terms the measurement of the altitude or azimuth of a heavenly body for navigational purposes.
    • Naval Terms the information obtained by such a measurement.
11. [Obs.] observance, as of the law.

• Latin observātiōn- (stem of observātiō), equivalent. to observāt(us) (past participle of observāre to observe) + -iōn- -ion
• Middle English 1350–1400

Synonyms

• 3. attention.
• 8. pronouncement, opinion. See remark. 

Collins Concise English Dictionary © HarperCollins Publishers::

observation / ˌɒbzəˈveɪʃən/ noun

1. the act of observing or the state of being observed
2. a comment or remark
3. detailed examination of phenomena prior to analysis, diagnosis, or interpretation: the patient was under observation
4. the facts learned from observing
5. an obsolete word for observance
6. a sight taken with an instrument to determine the position of an observer relative to that of a given heavenly body
7. the data so taken

ˌobserˈvational adjective

ˌobserˈvationally adverb