I don't think that there is a different term for what you are describing, because it is effectively the same as cadence.

Thinking as I type here...
For a given speed (m/s) (v=s/t), the wheel rotates at a certain rate (vr=(2pi(s/2.02))/t) (i.e., angular rotation of the wheel per second, assuming 700x23 tires). The rotational velocity of the wheel is directly related to the minimum rpms of the crank by the gear ratio (chainring/cog). So, in order to find the necessary angular rotation of the crank per second you would simply multiply by the reciprocal ((cog/chainring)*(2pi(s/2.02))/t).

All of this calculates the minimum cadence for a given velocity and gear ratio, but it is also a backwards way of describing how cadence and gear ratio determine velocity. In other words, given any two of the three variables, the other necessarily follows.

What you are talking about is the same as cadence.