How is it that a rut is a sort of a groove

[conuly]

but getting into a groove and getting into a rut are two entirely different things?

Comments

[ncp.livejournal.com]

I think "getting into the groove" is a more recent expression, from record players, when the needle would be "in the groove" and the music was playing and everything was, well, groovy.

Dunno about "in a rut" I think it's gotta do with farming.

[conuly]

A rut is, specifically, a track caused by a wheel or "habitual passage", or a groove in which something runs. Ruts built specifically to ease transport are called "wagonways" and are the origin of modern railways.