Just avoided using the word #diffeomorphism in a paper, which is a win for everybody.

In differential geometry, a #diffeomorphism is called a motion if it induces an isometry between the tangent space at a manifold point and the tangent space at the image of that point

a #morphism between smooth varieties is #étale at a point iff the differential between the corresponding tangent spaces is an #isomorphism. This is in turn precisely the condition needed to ensure that a map between manifolds is a local #diffeomorphism

a #morphism between smooth varieties is #étale at a point iff the differential between the corresponding tangent spaces is an #isomorphism. This is in turn precisely the condition needed to ensure that a map between manifolds is a local #diffeomorphism