Swimmers often talk in hushed tones about the "catch", and it isn't when you get a guppy in your mouth. It's an elusive feeling of balance, comfort and (dare I say it?) oneness with the water, that comes after acquiring good balance and when working out at least three times a week.
Back when I used to swim under coaching, I used to get it... hmm that makes it sound like a disease... I used to experience it, and it was a good feeling. But as I said, it's elusive. Take two too many days off and it goes away. Or some days you're just tired and the catch just doesn't bite.
Catch must exist with any oft-repeated motor-activity. I remember reading a quote in Readers Digest that was attributed to Pandit Ravi Shankar and went something like this: If I don't practice for one day, I notice it. If I don't practice for two days, my accompanists notice it. If I don't practice for three days, the critics notice it. If I don't practice for four days, the audience notices it.
Runners also talk about days when they feel they're just flowing over the ground. And yes, I definitely think there's catch with cycling. Some days, you and the bike are one and the pedalling just flows. The more you ride, the more frequent these days become, until days without the catch are the exceptions. Until you run into a bad week that is. It's not quite as elusive as the swimming catch, but it is hard to pin down. It needs a different word though, and unless I've missed reading about it somewhere, it seems to have been left up to you and me to come up with one.