/sci/ - Science & Math

Happy holidays!
In an ODE a change of variables of the form [math] z=f(y,x), ~t=g(y,x) [/math] is called a point transformation. My question is: is there a similar name for a transformation involving the first derivative, e.g. [math] z=f(y',y),~t=g(y',y) [/math], where [math] '=\frac{\mathrm{d}}{\mathrm{d} x} [/math]. Or perhaps there's a name for a specific transformation [math] z=y',~t=y[/math]? Or at least a worthy article or review of the topic?