an act or instance of noticing or perceiving.

an act or instance of regarding attentively or watching.

the faculty or habit of observing or noticing.

notice

to escape a person's observation.

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.

the information or record secured by such an act.

something that is learned in the course of observing things

My observation is that such clouds mean a storm.

a remark, comment, or statement based on what one has noticed or observed.

the condition of being observed.

Navigation .

the measurement of the altitude or azimuth of a heavenly body for navigational purposes.

the information obtained by such a measurement.

Obsolete . observance, as of the law.

noun

heedlessness , inattention , indifference , neglect , thoughtlessness , no comment

noun

ascertainment , check , cognition , cognizance , conclusion , consideration , detection , estimation , examination , experience , heedfulness , information , inspection , investigation , knowledge , mark , measurement , mind , monitoring , note , notice , noticing , once-over * , overlook , perception , probe , recognizing , regard , remark , research , review , search , study , supervision , surveillance , view , watchingnotes:observance refers to the following of a custom , duty , or law; observation refers to the act of noticing or recording , annotation , catch phrase , comeback , commentary , crack * , finding , mention , mouthful * , obiter dictum , opinion , pronouncement , reflection , saying , say so , thought , utterance , wisecracknotes:observance refers to the following of a custom , attention , espial , heed , observance , scrutiny , autopsy , comment , discovery , survey