IPA: /dɪˈspɛnsəˌtɔːri/
KK: /dɪˈspɛnsəˌtɔri/
A book that explains how to prepare and use medicines, often serving as a guide for pharmacists.
The pharmacist referred to the dispensatory to find the correct dosage for the medication.
Dispensatory is formed from "dis-" (meaning apart) and "pensare" (meaning to weigh or consider). The term originally referred to a place or system where substances are weighed out or distributed, particularly in the context of medicine.
Think of 'weighing out' ('pensare') substances 'apart' ('dis-') — that's why dispensatory refers to a place where medicines are prepared and distributed.