An ITICMaterialDefinition is an ITICMaterial's definition.
You can use this to retrieve some information on the ITICMaterial object.

It might be required for you to import the package if you encounter any issues, so better be safe than sorry and add the import.
import modtweaker.tconstruct.ITICMaterialDefinition;

You can retrieve an ITICMaterialDefinition from an ITICMaterial's definition ZenGetter:

ZenScript
 Copy
val def = <ticmat:stone>.definition;

ZenGetter	Return Type	Description
ZenGetter name	Return Type string	Description The material's internal name
ZenGetter displayName	Return Type string	Description The material's localized name