Inductor dimensions as a function of time(?)
Note that these dimensions will be functions of time if the geometry of the inductor varies.

The 'geometry' of a toroid could be thought of as a topology, and a few dimensions. The topology is the fact that it's a toroid, and the dimensions are the length and cross section of the ring.
If the geometry varies, then the dimensions vary, by definition. If they vary with time, then they vary with time. The author is stating a tautology (something that's automatically true by definition or by construction) that's unhelpful and confusing, at least in the case of the toroid, which tends not to vary its dimensions.
There are inductors that vary their dimensions with time.
One type of pulse generator sets up a magnetic field in an inductor, then uses explosives to rapidly compress the inductor into a smaller volume. These are single-use!
A railgun uses two parallel rails, with the projectile forming a shorting link between them. As the projectile moves along the rails, the loop area enclosed by the rail, projectile, return rail loop changes, and so does the inductance. One of the design parameters quoted for any given railgun design is the change in inductance per distance of projectile movement.