Engrooved isn't a word, so I'm looking for something that carries its meaning. Engraved, accustomed, and other synonyms don't express the same meaning. I'm looking for a word that carries the meaning "fitted to something". E.g.,
The keys were engrooved to the fingers.
Edit: so "adapted over time" is the best fit so far (thanks to FumbleFingers). If anyone has a better way to express this, I'd love to hear it.