observation observation /ˌɑːbzɝˈveɪʃən/

noun

1. () The act of making and recording a measurement  ( observation )
   the act of making and recording a measurement
   
2. () The act of observing; taking a patient look  ( observance , watching , observation )
   the act of observing; taking a patient look
     The scientist made a groundbreaking observation during the experiment.
   The scientist made a groundbreaking observation during the experiment.
   
3. () The act of noticing or paying attention  ( observance , observation , notice )
   the act of noticing or paying attention
    He escaped the notice of the police
   he escaped the notice of the police
   
4. () Facts learned by observing  ( observation )
   facts learned by observing
    He reported his observations to the mayor
   he reported his observations to the mayor
   
5. () A remark expressing careful consideration  ( reflection , reflexion [British] , observation )
   a remark expressing careful consideration