Observer n. : One who observes, or pays attention to, anything; especially, one engaged in, or trained to habits of, close and exact observation; as, an astronomical observer.

Observer n. : One who keeps any law, custom, regulation, rite, etc.; one who conforms to anything in practice.

Observer n. : One who fulfills or performs; as, an observer of his promises.

Observer n. : A sycophantic follower.

Example:
What is the apparent frequency heard by an Observer standing at the station?

Taxonomy
Real Estate, Gossip, Movies, Theater, new york, Media News, The New York, New York Observer, Conde Nast, New York Times, Reichl, Reid, Treament, Chuck Schumer, Fashion Week, Manhattan, York Politics, Steve Kornacki.

Defination from the web:
Weekly covering media and society, arts and entertainment, opinions, politics, and business and real estate of Manhattan and the world.