What is the meaning of Observer?

One who makes observations, monitors or takes notice

One who adheres or follows laws, guidelines, etc.

A person sent as a representative, to a meeting or other function to monitor but not to participate

A country or other entity which has limited participation rights within an organization.

A crew member on an aircraft who makes observations of enemy positions or aircraft

A sentry etc. manning an observation post

to observe, watch

to note, notice

to keep, maintain

first-person singular present passive subjunctive of observō

imperative of observere

Source: wiktionary.org