a long narrow channel or depression, e.g. one cut into a length of wood, stone, etc
the continuous spiral track on a record, whose irregularities correspond to the recorded sounds
a fixed routine; a rut
in the groove
informal performing at one's peak
dated, informal having an enjoyable time
informal the state of performing at one's peak; top form
He's a great talker when he is in the groove
dated, informal an enjoyable or exciting experience
[Middle English groof mine, mineshaft, from Dutch groeve pit; related to Old English grafan grave3]