Is orbit a word in the Scrabble Dictionary

Yes, orbit is playable

...and is worth 8 points.

Found in the following dictionaries

Enable (Words with friends)
SOWPODS (Collins Scrabble Words)
OTCWL2014 (NASPA Word List 2014)
TWL06 (NASPA List 2006)

"Orbit" Definition

noun

A range of activity, experience, or knowledge.
A range of control or influence: "What magnetism drew these quaking ruined creatures into his orbit?” ( Malcolm Lowry). See Synonyms at range.
Either of two bony cavities in the skull containing an eye and its external structures; an eye socket.
One complete revolution of such a body.
The path of a body in a field of force surrounding another body; for example, the movement of an atomic electron in relation to a nucleus.

verb

To revolve in an orbit around .
To send up and make revolve in an orbit .
To travel in circles.

verb-intransitive

To move in an orbit.

verb-transitive

To put into an orbit: orbit a satellite.
To revolve around (a center of attraction): The moon orbits Earth.