substrate = ?

A scientific question again?

substrate = The supporting medium that allows a structure to grow.

* Substrate (building), Natural stone, masonry surface, ceramic & porcelain tiles
* Substrate (aquarium), the material used in the bottom of an aquarium
* Substrate (vivarium), the material used in the bottom of a Vivarium or Terrarium.
* Substrate (biochemistry), a molecule that is acted upon by an enzyme
* Substrate (materials science), the material on which a process is conducted
* Substrate (biology), the natural environment in which an organism lives, or the surface or medium on which an organism grows or is attached [1]With certain attached organisms (such as corals) substrate thus only refers to the solid surface to which it is attached, and not to the permeable material that surrounds it.
* Substrate (chemistry), the reactant which is consumed during a catalytic or enzymatic reaction
* Substrate (marine biology), the earthy material that exists in the bottom of a marine habitat, like dirt, rocks, sand, or gravel
* Substrate (playground equipment), non-edible material
* Substrate (printing), the base material that images will be printed onto
* The stratum on which another geologic stratum lies

Substrate (semiconductor): In electronic wafers and thin film electronics, the physical material upon which a semiconductor device, e.g. a photovoltaic cell or an integrated circuit is applied. (e.g. glass or aluminum oxide).

Thank you Dadpad.

What is gear here?

This car has three gears?

The same are they?

Gears are wheels with teeth on them that are used in mechanical devices to step up or down speeds. Another word is cog.

Thank you.

I guessed that at the beginning. What has confused me is that common sense tells us the ancient computer was made of gears.