A graduator can be defined as the person who shows or indicates graduation. Also, it can be defined as the instrument which is helping in diving the straight line or curve at regular intervals. So graduator stands for the instrument and the person who indicates graduation is also referred to as graduators (https://planet-herbal.com/tag/tips-for-graduators/). One more meaning is there which means an apparatus for diffusing some of the wine or some solution. So graduator holds three meanings.