designating or of a technique used to test objectively the effects of a drug, course of treatment, etc. in which the researchers but not the subjects know during the testing who is actually receiving the drug, treatment, etc.
Single-blind. (n.d.). In YourDictionary. Retrieved from https://www.yourdictionary.com/single-blind
Describing an experiment (usually medical) in which the identity of those repeating different treatments is kept secret from the subjects, but not the administrators, until the outcome of the experiment is known.
English Wiktionary. Available under CC-BY-SA license.