Officinal

Officinal drugs, plants and herbs are those which are sold in a chemist or druggist shop. Officinal medical preparations of such drugs are made in accordance with the prescriptions authorized by a pharmacopoeia. "Officinal" is not related to the word "official". The classical Latin "officina" meant a workshop, manufactory, laboratory, and in medieval Latin was applied to a general storeroom. It thus became applied to a shop where goods were sold rather than a place where things were made. Whereas official descends from officium, meaning office, as in duty or position.
In botanical nomenclature, the specific epithet "officinalis" derives from a plant's historical use in pharmacology.