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	Возвращаемый тип	Описание
ZenGetter name	Возвращаемый тип string	Описание The material's internal name
ZenGetter displayName	Возвращаемый тип string	Описание The material's localized name